CN110998953B

CN110998953B - Solid electrolyte composition, solid electrolyte-containing sheet and all-solid-state secondary battery, and method for producing solid electrolyte-containing sheet and all-solid-state secondary battery

Info

Publication number: CN110998953B
Application number: CN201880048423.7A
Authority: CN
Inventors: 三村智则; 望月宏显
Original assignee: Fujifilm Corp
Current assignee: Fujifilm Corp
Priority date: 2017-07-21
Filing date: 2018-07-17
Publication date: 2023-06-23
Anticipated expiration: 2038-07-17
Also published as: US11482726B2; CN110998953A; US20200153042A1; JPWO2019017311A1; WO2019017311A1; JP6854347B2

Abstract

The present invention provides a solid electrolyte composition, a solid electrolyte-containing sheet and an all-solid secondary battery obtained by using the solid electrolyte composition, and a method for producing the solid electrolyte-containing sheet and the all-solid secondary battery, wherein the solid electrolyte composition comprises: a polymer (A) having a mass average molecular weight of 5000 or more; an electrolyte salt (B) having ions of a metal belonging to group 1 or group 2 of the periodic table; a compound (C) having 3 or more polymerization-reactive groups; and a compound (D) having 2 or more polymerization-reactive groups which are different from the polymerization-reactive groups of the compound (C) and which are capable of undergoing polymerization reaction with the polymerization-reactive groups of the compound (C).

Description

Solid electrolyte composition, solid electrolyte-containing sheet and all-solid-state secondary battery, and method for producing solid electrolyte-containing sheet and all-solid-state secondary battery

Technical Field

The present invention relates to a solid electrolyte composition, a sheet containing a solid electrolyte, an all-solid secondary battery, and a method for producing a sheet containing a solid electrolyte and an all-solid secondary battery.

Background

A lithium ion secondary battery is a battery that has a negative electrode, a positive electrode, and an electrolyte sandwiched between the negative electrode and the positive electrode, and is configured to be chargeable and dischargeable by reciprocating lithium ions between the two electrodes. In a lithium ion secondary battery, an organic electrolytic solution has been conventionally used as an electrolyte. However, the organic electrolyte is liable to leak liquid, and there is a possibility that short circuit occurs inside the battery by overcharge or overdischarge to cause ignition, and further improvement of safety and reliability is demanded.

As a secondary battery capable of improving safety and the like which are problems of a lithium ion secondary battery using an organic electrolytic solution, an all-solid-state secondary battery in which all of a negative electrode, an electrolyte, and a positive electrode are composed of a solid is being studied.

For example, an all-solid-state secondary battery using a (dry) polymer electrolyte instead of an organic electrolyte may be cited. As such an all-solid-state secondary battery, for example, patent document 1 describes a secondary battery using an electrolyte including: a 1 st polymer compound having a crosslinked structure in which a (meth) acrylate compound is crosslinked by chain polymerization (radical polymerization) of a carbon-carbon double bond; a compound 2; at least 1 kind of 3 rd compound having a molecular weight larger than that of the 2 nd compound and 2 nd polymer compound having a crosslinked structure in which the 3 rd compound is crosslinked; and an electrolyte salt. Patent document 2 describes a secondary battery using an electrolyte including: a compound wherein a (meth) acrylate compound having an ether bond and a crosslinking group is crosslinked by a crosslinking group ((meth) acryl) by radical polymerization of a carbon-carbon double bond; an electrolyte salt; and a polymer compound for dissolving the electrolyte salt.

Technical literature of the prior art

Patent literature

Patent document 1: japanese patent laid-open No. 2003-229019

Patent document 2: japanese patent laid-open No. 2000-222939

Disclosure of Invention

Technical problem to be solved by the invention

As a polymer capable of imparting ion conductivity to the polymer electrolyte by dissolving an electrolyte salt in the polymer electrolyte, mainly used are polyalkylene oxides such as polyethylene oxide (PEO), and polymers (polyethers) having an alkyleneoxy group in a part of the molecular structure. When an all-solid-state secondary battery containing a polymer electrolyte of this type is used (repeatedly charged and discharged), lithium precipitates in dendrites (dendrites) by a reduction reaction of lithium ions, thereby causing short-circuiting and causing abnormal voltage behaviors (poor durability) such as voltage drop. The present inventors have studied all-solid-state secondary batteries using a polymer electrolyte from the viewpoint of further improving the ion conductivity required for all-solid-state secondary batteries in recent years in response, and have found that durability of all-solid-state secondary batteries is significantly impaired by improving ion transport performance of the polymer electrolyte. On the other hand, it is also known that, when the degree of crosslinking of the polymer compound or the (meth) acrylate compound contained in the polymer electrolyte described in patent documents 1 and 2 is increased, improvement in durability is expected, and the ionic conductivity is lowered, so that the above-mentioned requirements cannot be satisfied.

The present invention addresses the problem of providing a solid electrolyte composition which, when used as a layer structure material for an all-solid secondary battery, can impart not only high ionic conductivity but also excellent durability to the obtained all-solid secondary battery. The present invention also provides a solid electrolyte-containing sheet obtained using the solid electrolyte composition and an all-solid-state secondary battery. Further, the present invention also provides a method for producing each of the solid electrolyte-containing sheet and the all-solid secondary battery.

Means for solving the technical problems

As a result of intensive studies by the present inventors, it was found that: a composition containing a polymer compound (in the present invention, simply referred to as a polymer) (a) having a mass average molecular weight of 5000 or more, an electrolyte salt (B) having an ion of a metal belonging to group 1 or group 2 of the periodic table, a compound (C) having 3 or more polymerization-reactive groups, and a compound (D) having 2 or more polymerization-reactive groups which are different from the polymerization-reactive groups of the compound (C) and which can be polymerized with the polymerization-reactive groups of the compound (C) can be preferably used as a layer structure material of an all-solid secondary battery, and further, the composition can be used to form a structural layer of an all-solid secondary battery by polymerizing the compound (C) and the compound (D) in the presence of the polymer (a) and the electrolyte salt (B), whereby high ionic conductivity and excellent durability can be imparted to the all-solid secondary battery. The present invention has been further studied based on this knowledge, and has completed the present invention.

That is, the above problems are solved as follows.

< 1 > a solid electrolyte composition comprising: a polymer (A) having a mass average molecular weight of 5000 or more; an electrolyte salt (B) having ions of a metal belonging to group 1 or group 2 of the periodic table; a compound (C) having 3 or more polymerization-reactive groups; and a compound (D) having 2 or more polymerization-reactive groups which are different from the polymerization-reactive groups of the compound (C) and which are capable of undergoing polymerization reaction with the polymerization-reactive groups of the compound (C).

< 2 > the solid electrolyte composition according to < 1 >, wherein,

the polymerization-reactive group of the compound (C) and the polymerization-reactive group of the compound (D) are each 1 kind of polymerization-reactive group selected from the following polymerization-reactive group (a).

< group (a) >, a polymerization-reactive group

Hydroxy, amino, carboxyl, alkoxycarbonyl, haloformyl, sulfo, carbamoyl, formyl, isocyanate, oxetanyl, epoxy, dicarboxylic anhydride, silyl, alkynyl, alkenyl, bromo, chloro, iodo, diazo, azido, nitrile oxide

< 3 > the solid electrolyte composition according to < 1 > or < 2 >, wherein,

The following formula (R) ^G ) Ratio R of defined polymerization-reactive groups ^G Greater than 0.8 and less than 1.2.

(R) ^G )：R ^G = [ number of polymerization-reactive groups in molecule of compound (C) 1×content (mol) of compound (C) in solid electrolyte composition]Number of polymerization-reactive groups in molecule of Compound (D) 1X content (mol) of Compound (D) in solid electrolyte composition]

A solid electrolyte composition according to any one of < 1 > to < 3 >, wherein,

the combination of the polymerization-reactive group of the compound (C) and the polymerization-reactive group of the compound (D) is any one of the following combinations (C1) to (C9).

< combination of polymeric reactive groups >

A solid electrolyte composition according to any one of < 1 > to < 4 >, wherein,

the combination of the polymerization-reactive group of the compound (C) and the polymerization-reactive group of the compound (D) is any one of the following combinations (C3), (C4), and (C6) to (C8).

< combination of polymeric reactive groups >

(C3) Amino-oxetanyl (C4) amino-epoxy

(C6) Epoxy-carboxy (C7) azido-alkynyl

(C8) Oxidized nitrile-alkynyl

A solid electrolyte composition according to any one of < 1 > to < 5 >, wherein,

The content of the polymer (a), the electrolyte salt (B), the compound (C) and the compound (D) in the solid electrolyte composition is, in terms of mass ratio, polymer (a), electrolyte salt (B), compound (C) and compound (D) =1:0.05 to 2.50:0.04 to 2:0.04 to 2.

A solid electrolyte composition according to any one of < 1 > to < 6 >, wherein,

the compound (D) has 3 or more polymerization-reactive groups.

< 8 > the solid electrolyte composition according to any one of < 1 > to < 7 >, which contains the inorganic solid electrolyte (E).

< 9 > the solid electrolyte composition according to any one of < 1 > to < 8 >, which contains the active material (F).

< 10 > the solid electrolyte composition according to any one of < 1 > to < 9 >, which contains the solvent (G).

< 11 > the solid electrolyte composition according to < 10 >, wherein,

the solid content concentration is 5 to 40 mass%.

< 12 > a solid electrolyte-containing sheet having a layer composed of the solid electrolyte composition as described in any one of < 1 > to < 11 > above.

A solid electrolyte-containing sheet according to < 13 > to < 12 > having a polymer (A), an electrolyte salt (B) and a reactant of the compound (C) and the compound (D).

< 14 > an all-solid-state secondary battery comprising: a positive electrode active material layer, a negative electrode active material layer, and a solid electrolyte layer between the positive electrode active material layer and the negative electrode active material layer, wherein,

at least 1 of the positive electrode active material layer, the negative electrode active material layer, and the solid electrolyte layer is a layer composed of the solid electrolyte composition described in any one of < 1 > to < 11 >.

< 15 > the all-solid secondary battery according to < 14 >, wherein,

at least 1 of the positive electrode active material layer, the negative electrode active material layer, and the solid electrolyte layer contains an inorganic solid electrolyte.

< 16 > the all-solid secondary battery according to < 14 > or < 15 >, wherein,

the negative electrode active material layer is a lithium layer.

< 17 > a method for producing a solid electrolyte-containing sheet, wherein,

the solid electrolyte composition according to any one of < 1 > to < 11 > is prepared by polymerizing the compound (C) and the compound (D) in the presence of the polymer (A) and the electrolyte salt (B).

< 18 > a method for manufacturing an all-solid secondary battery by the manufacturing method described above as < 17 >.

In the description of the present invention, the numerical range indicated by "to" means a range including numerical values before and after "to" as a lower limit value and an upper limit value.

Effects of the invention

The solid electrolyte composition and the solid electrolyte-containing sheet of the present invention can impart ion conductivity and durability to an all-solid secondary battery at a high level by being used as a layer structure material of the all-solid secondary battery or a layer constituting the all-solid secondary battery, respectively. Further, the all-solid-state secondary battery of the present invention exhibits high ionic conductivity and excellent durability. Further, the method for producing a solid electrolyte-containing sheet and the method for producing an all-solid-state secondary battery according to the present invention can produce a solid electrolyte-containing sheet and an all-solid-state secondary battery that exhibit the above-described excellent characteristics.

The above features and other features and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings.

Drawings

Fig. 1 is a longitudinal sectional view schematically showing an all-solid-state secondary battery according to a preferred embodiment of the present invention.

Fig. 2 is a longitudinal sectional view schematically showing the button all-solid-state secondary battery fabricated in the example.

Detailed Description

In the description of the present invention, the expression "compound" (for example, when the compound is added to the end of the description), is used to indicate that the compound itself includes a salt or ion thereof. Further, it is intended to include derivatives in which a part of the substituents are introduced so as not to impair the desired effect.

In the present invention, the term "unsubstituted or substituted (the same applies to the linking group and the like) means that an appropriate substituent may be further provided. The meaning is also the same for the compounds which are not indicated as substituted or unsubstituted. The substituent which may be further provided may preferably be the following substituent T. The number of carbon atoms of a substituent further having an appropriate substituent means the total number of carbon atoms including the number of carbon atoms of the appropriate substituent.

In the present invention, when a plurality of substituents, linking groups, and the like (hereinafter referred to as substituents, and the like) represented by specific symbols are present, or when a plurality of substituents, and the like, are simultaneously or alternatively defined, it means that the substituents, and the like, may be the same or different from each other. When plural substituents are adjacent to each other, these may be linked or condensed to form a ring, unless otherwise specified.

In the present invention, when simply expressed as "acrylic acid" or "(meth) acrylic acid", it means acrylic acid and/or methacrylic acid. Also, when simply expressed as "acryl" or "(meth) acryl", acryl and/or methacryl is expressed, and when expressed as "acrylate" or "(meth) acrylate", acrylate and/or methacrylate is expressed.

In the present invention, unless otherwise specified, the mass average molecular weight (Mw) can be measured as a molecular weight in terms of polyethylene glycol by gel permeation chromatography (Gel Permeation Chromatography: GPC). The measurement was performed by the method of the following conditions. Wherein a suitable eluent is suitably selected according to the measured polymer.

(conditions)

Chromatographic column: chromatography columns were used to which TOSOH TSKgel Super HZM-H (trade name), TOSOH TSKgel Super HZ4000 (trade name), TOSOH TSKgel Super HZ2000 (trade name) were attached.

And (3) a carrier: n-methylpyrrolidone

Measuring temperature: 40 DEG C

Carrier flow rate: 1.0mL/Min

Sample concentration: 0.1 mass%

A detector: RI (refractive index) detector

[ solid electrolyte composition ]

First, the solid electrolyte composition of the present invention will be described.

The solid electrolyte composition of the present invention contains a polymer (A) having a mass average molecular weight of 5000 or more, an electrolyte salt (B) having an ion of a metal belonging to group 1 or group 2 of the periodic table, a compound (C) having 3 or more polymerization-reactive groups, and a compound (D) having 2 or more polymerization-reactive groups which are different from the polymerization-reactive groups of the compound (C) and are capable of undergoing polymerization reaction with the polymerization-reactive groups of the compound (C).

In the present invention, the solid electrolyte composition containing the polymer (a) and the electrolyte salt (B) means that the solid electrolyte composition contains the polymer (a) as an ion conductor in which the electrolyte salt (B) is dissolved (dispersed) in addition to the polymer (a) and the electrolyte salt (B) as separate compounds.

In the present invention, the solid electrolyte composition contains the compound (C) and the compound (D), and the solid electrolyte composition contains the compound (C) and the compound (D) as separate compounds (in an unreacted state), and also contains a reaction product obtained by polymerizing a polymerization-reactive group containing the compound (C) and a polymerization-reactive group containing the compound (D). In the form of containing the reactant, the reactant that is not formed into a sheet is referred to as a solid electrolyte composition.

The solid electrolyte composition of the present invention is a material for forming a solid electrolyte layer (polymer electrolyte).

The solid electrolyte composition of the present invention is used as the above-mentioned layer structure material, and if the compound (C) and the compound (D) are polymerized in the presence of the polymer (a) and the electrolyte salt (B) to form a structural layer of an all-solid-state secondary battery, it is possible to impart high ion conductivity and excellent durability to the all-solid-state secondary battery.

Although the reason for this is not clear, it is considered as follows. Specifically, as will be described later in detail, regarding the polymerization reaction of the compound (C) and the compound (D), the conditions thereof, and the like, when the two compounds are polymerized in the presence of the polymer (a) and the electrolyte salt (B), the ion conductor including the polymer (a) and the electrolyte salt (B) and the matrix site (matrix network) including the polymerization reaction product of the two compounds can be formed in a state of being substantially uniformly dispersed or mixed to exhibit interaction. Further, regarding the base portion, it is considered that the polymerization reactive groups of the two compounds react with each other to form a reaction portion (crosslinked structure) more uniform than a reaction portion formed by, for example, a chain reaction (polymerization). In this way, functional separation of the ion conductor from the base portion is achieved, and the mechanical strength of the reactant of the solid electrolyte composition (the film strength of the solid electrolyte-containing sheet) can be improved without decreasing the ion conductivity of the ion conductor. Therefore, the all-solid-state secondary battery of the present invention using the solid electrolyte composition (solid electrolyte-containing sheet) of the present invention exhibits high ion conductivity (is low resistance), and is suppressed in voltage abnormality behavior or occurrence of short circuit during charge and discharge, and exhibits excellent battery performance.

In the present invention, the crosslinked structure means a bridge structure, a three-dimensional network structure, a branched structure, and the like, which include polymers.

Polymer (A) >

The polymer (a) is a polymer which forms an ion conductor by dissolving the electrolyte salt (B). The polymer (a) is not particularly limited as long as it has a property of ion conductivity together with the electrolyte salt (B), and a polymer that is generally used for a polymer electrolyte for an all-solid-state secondary battery can be cited. Here, the ionic conductivity exhibited by the polymer (a) and the electrolyte salt (B) is a characteristic of conducting ions of a metal belonging to group 1 or group 2 of the periodic table, and is not particularly limited as long as the ionic conductivity exhibits a desired function as a polymer electrolyte.

The state of inclusion is not particularly limited as long as the polymer (a) is contained in the solid electrolyte composition. For example, the polymer (a) may be contained in part or whole (in a free state), and is preferably contained as an ion conductor together with the electrolyte salt (B). The electrolyte salt (B) is dissolved (dispersed) by the polymer (a) to form an ion conductor. In the ion conductor, the electrolyte salt (B) is usually dissociated into cations and anions, but may also contain undissociated salts.

The mass average molecular weight of the polymer (A) is more than 5000. The solid electrolyte composition of the present invention can impart high ion conductivity to an all-solid-state secondary battery by containing a polymer (a) having a mass average molecular weight of 5000 or more. The mass average molecular weight of the polymer (a) is preferably 20000 or more, more preferably 50000 or more, and even more preferably 80000 or more, from the viewpoint of ion conductivity. On the other hand, from the viewpoint of process suitability, the mass average molecular weight is preferably 10000000 or less, more preferably 1000000 or less, and further preferably 300000 or less.

The mass average molecular weight of the polymer (A) was measured by the above-mentioned measurement method.

The polymer (a) is preferably at least 1 selected from the group consisting of polyether, polysiloxane, polyester, polycarbonate, polyurethane, polyurea, and polyacrylate.

The polyether is preferably a polymer compound having a repeating unit represented by the following formula (1-1).

[ chemical formula 1]

L ¹ Represents a linking group, preferably an alkylene group (preferably having 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms, particularly preferably 1 to 4 carbon atoms), alkenylene group(preferably 2 to 12 carbon atoms, more preferably 2 to 6 carbon atoms, particularly preferably 2 to 4 carbon atoms), arylene (preferably 6 to 22 carbon atoms, more preferably 6 to 14 carbon atoms, particularly preferably 6 to 10 carbon atoms), or a combination of these. The linking group may have a substituent T (preferably, except for the polymerization-reactive groups of the compounds (C) and (D)) described later. Of these, alkylene groups having 1 to 4 carbon atoms are particularly preferable.

The presence of a plurality of L's in the molecule ¹ May be the same as or different from each other.

The repeating unit represented by the formula (1-1) is preferably present in the molecule in a molar ratio of 50% or more, more preferably 60% or more, and particularly preferably 70% or more. The upper limit is 100%. The molar ratio can be calculated from analysis by nuclear magnetic resonance spectroscopy (NMR) or the like, or from the molar ratio of the monomers used in the synthesis. The following is the same.

The polysiloxane is preferably a polymer compound having a repeating unit represented by the following formula (1-2).

[ chemical formula 2]

R ¹ R is R ² Represents a hydrogen atom, a hydroxyl group, an alkyl group (preferably having 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms, particularly preferably 1 to 3 carbon atoms), an alkenyl group (preferably having 2 to 12 carbon atoms, more preferably 2 to 6 carbon atoms, particularly preferably 2 or 3 carbon atoms), an alkoxy group (preferably having 1 to 24 carbon atoms, more preferably 1 to 12 carbon atoms, further preferably 1 to 6 carbon atoms, particularly preferably 1 to 3 carbon atoms), an aryl group (preferably having 6 to 22 carbon atoms, more preferably 6 to 14 carbon atoms, particularly preferably 6 to 10 carbon atoms), an aralkyl group (preferably having 7 to 23 carbon atoms, more preferably 7 to 15 carbon atoms, particularly preferably 7 to 11 carbon atoms). The alkyl group, alkenyl group, aryl group, and aralkyl group may have a substituent T (preferably, except for the polymerization-reactive group of the compounds (C) and (D)) described later, respectively. Among them, alkyl groups having 1 to 3 carbon atoms, alkoxy groups having 1 to 12 carbon atoms, or phenyl groups are particularly preferable. R is R ¹ R is R ² May be the same or different.

The repeating units represented by the formula (1-2) are preferably present in the molecule in a molar ratio of 50% or more, more preferably 60% or more, particularly preferably 70% or more. The upper limit is 100%.

The polyester is preferably a polymer compound having a repeating unit represented by the following formula (1-3).

[ chemical formula 3]

L ² Represents a linking group, and L in the above formula (1-1) ¹ Meaning the same.

The repeating units represented by the formulae (1-3) are preferably present in the molecule in a molar ratio of 50% or more, more preferably 60% or more, particularly preferably 70% or more. The upper limit is 100%.

The polycarbonate, polyurethane and polyurea are preferably polymer compounds each having a repeating unit represented by the following formula (1-4).

[ chemical formula 4]

L ³ Represents a linking group, and L in the above formula (1-1) ¹ Meaning the same.

X and Y each independently represents O or NR ^N 。R ^N Preferably a hydrogen atom, an alkyl group (preferably having 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms, particularly preferably 1 to 3 carbon atoms), an alkenyl group (preferably having 2 to 12 carbon atoms, more preferably 2 to 6 carbon atoms, particularly preferably 2 or 3), an aryl group (preferably having 6 to 22 carbon atoms, more preferably 6 to 14 carbon atoms, particularly preferably 6 to 10 carbon atoms), or an aralkyl group (preferably having 7 to 23 carbon atoms, more preferably 7 to 15 carbon atoms, particularly preferably 7 to 11 carbon atoms). Among them, a hydrogen atom or an alkyl group having 1 to 2 carbon atoms is particularly preferable.

The repeating units represented by the formulae (1-4) are preferably present in the molecule in a molar ratio of 50% or more, more preferably 60% or more, particularly preferably 70% or more. The upper limit is 100%.

The polyacrylate is preferably a compound having a repeating unit represented by the following formula (1-5).

[ chemical formula 5]

L ⁴ Is a methylene group which may have a substituent (preferably an alkyl group having 1 to 3 carbon atoms, a phenyl group, a fluorine atom or a chlorine atom).

R ³ Represents a hydrogen atom, a halogen atom, a methyl group, an ethyl group, a cyano group or a hydroxyl group, and particularly preferably a hydrogen atom or a methyl group.

R ⁴ Represents a hydrogen atom, an alkyl group (preferably having 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms, particularly preferably 1 to 3 carbon atoms), an alkenyl group (preferably having 2 to 12 carbon atoms, more preferably 2 to 6 carbon atoms, particularly preferably 2 or 3 carbon atoms), an aryl group (preferably having 6 to 22 carbon atoms, more preferably 6 to 14 carbon atoms, particularly preferably 6 to 10 carbon atoms), an aralkyl group (preferably having 7 to 23 carbon atoms, more preferably 7 to 18 carbon atoms, particularly preferably 7 to 12 carbon atoms), a polyether group (preferably polyethylene oxide, polypropylene oxide, polybutylene oxide) or a polycarbonate group, particularly preferably polyethylene oxide (hydrogen atom or methyl end) or polypropylene oxide (hydrogen atom or methyl end). The R is ⁴ May have a substituent T (preferably, except for the polymerization-reactive groups of the compounds (C) and (D)).

The presence of a plurality of L's in the molecule ⁴ 、R ³ R is R ⁴ May be the same as or different from each other.

The repeating units represented by the formulae (1-5) are preferably present in the molecule in a molar ratio of 50% or more, more preferably 60% or more, particularly preferably 70% or more. The upper limit is 100%.

The polymer compound having a repeating unit represented by any one of the above formulas (1-1) to (1-5) may contain another repeating unit commonly used in each polymer compound.

Among these, polyethers such as polyethylene oxide (polyethylene glycol), polypropylene oxide (polypropylene glycol) and polytetramethylene ether glycol (polytetrahydrofuran), polysiloxanes such as polydimethylsiloxane, polyacrylates such as polymethyl methacrylate and polyacrylic acid, and polycarbonates are preferable as the polymer (a).

In the present invention, the polyacrylate contains a polymer compound having an optional substituent at the carbon atom in the α -position, and examples of the substituent include the above R ³ 。

As described above, since polyethers such as polyethylene oxide have low mechanical strength, there is room for improvement in terms of durability of all-solid-state secondary batteries when used as polymers for polymer electrolytes. However, in the present invention, since the ion conductor and the base portion exhibiting the above-described interaction can be constructed, high durability can be imparted to the all-solid-state secondary battery even if polyether is used. Thus, in the present invention, a polyether exhibiting high ionic conductivity together with the electrolyte salt (B), in particular, polyethylene oxide can be preferably used as the polymer of the polymer electrolyte.

The polymer (a) preferably has no group capable of undergoing polymerization reaction with the polymerization-reactive groups of the compound (C) and the compound (D) in the molecule (except the end of the molecular chain). The terminal group of the polymer (a) is not particularly limited, and examples thereof include a suitable group (e.g., a hydrogen atom, an alkyl group, and a hydroxyl group).

The molecular shape (molecular chain shape) of the polymer (a) is not particularly limited, and may be linear or branched, and preferably does not have a three-dimensional network structure.

The polymer (a) may be synthesized by a usual method, or may be commercially available.

The polymer (a) may be contained in the solid electrolyte composition singly or in combination of 1 or 2 or more.

Electrolyte salt (B) >)

The electrolyte salt (B) used in the present invention is a salt containing ions of a metal belonging to group 1 or group 2 of the periodic table. The electrolyte salt (B) is a metal salt that dissociates (generates) ions of a metal belonging to group 1 or group 2 of the periodic table as ions that travel between the positive electrode and the negative electrode by charging and discharging the all-solid-state secondary battery. The electrolyte salt (B) exhibits ion conductivity characteristics together with the polymer (a) by being dissolved in the polymer (a).

The state of inclusion is not particularly limited as long as the electrolyte salt (B) is contained in the solid electrolyte composition. For example, part or all of the electrolyte salt (B) may be contained alone (in a free state), and is preferably contained as an ion conductor together with the polymer (a). In the solid electrolyte composition, the electrolyte salt (B) may be partially dissociated, but is preferably dissociated into cations and anions.

The electrolyte salt (B) is not particularly limited as long as it exhibits the ionic conductivity, and electrolyte salts commonly used in polymer electrolytes for all-solid-state secondary batteries can be cited.

Among them, lithium salts are preferable, and metal salts (lithium salts) selected from the following (a-1) and (a-2) are preferable.

(a-1)：LiA _x D _y

A represents P, B, as, sb, cl, br or I or a combination of 2 or more elements selected from P, B, as, sb, cl, br and I. D represents F or O. x is an integer of 1 to 6, more preferably an integer of 1 to 3. y is an integer of 1 to 12, more preferably an integer of 4 to 6.

As LiA _x D _y Preferred specific examples of the metal salt represented are, for example, those selected from LiPF ₆ 、LiBF ₄ 、LiAsF ₆ LiSbF ₆ Inorganic fluoride salt of (2) and selected from LiClO ₄ 、LiBrO ₄ LiIO (LiIO) ₄ Is a high haloacid salt of (2).

(a-2)：LiN(R ^f SO ₂ ) ₂

R ^f Represents a fluorine atom or a perfluoroalkyl group. The number of carbon atoms of the perfluoroalkyl group is preferably 1 to 4, more preferably 1 to 2.

As LiN (R) ^f SO ₂ ) ₂ Preferable specific examples of the metal salt represented are, for example, those selected from LiN (CF ₃ SO ₂ ) ₂ 、LiN(CF ₃ CF ₂ SO ₂ ) ₂ 、LiN(FSO ₂ ) ₂ LiN (CF) ₃ SO ₂ )(C ₄ F ₉ SO ₂ ) Perfluoroalkyl sulfonyl imide salts of (c).

Among the above, the electrolyte salt (B) is preferably selected from LiPF from the viewpoint of ion conductivity ₆ 、LiBF ₄ 、LiClO ₄ 、LiBrO ₄ 、LiN(CF ₃ SO ₂ ) ₂ 、LiN(FSO ₂ ) ₂ LiN (CF) ₃ SO ₂ )(C ₄ F ₉ SO ₂ ) More preferably selected from LiPF ₆ 、LiBF ₄ 、LiClO ₄ 、LiN(CF ₃ SO ₂ ) ₂ LiN (FSO) ₂ ) ₂ Further preferably selected from LiClO ₄ 、LiN(CF ₃ SO ₂ ) ₂ LiN (FSO) ₂ ) ₂ Is a metal salt of (a) a metal salt of (b).

The electrolyte salt (B) may be synthesized by a usual method, or may be commercially available.

The electrolyte salt (B) may be contained in the solid electrolyte composition singly or in combination of 1 or 2 or more.

Compound (C) and compound (D) >

The compound (C) and the compound (D) are compounds that are reactants of the matrix site formed by performing a mutual polymerization reaction in a step of heating, for example, which will be described later, and may be referred to as precursor compounds of the matrix site.

In the present invention, the compound (C) has 3 or more 1 kind of polymerization-reactive groups, and the compound (D) has 2 or more 1 kind of polymerization-reactive groups.

The compound (D) may be any compound having a polymerization-reactive group which is different from the polymerization-reactive group of the compound (C) and is capable of reacting with the polymerization-reactive group of the compound (C), and the chemical structure other than the polymerization-reactive group (also referred to as a basic skeleton, a linking group, or the like) may be the same as or different from the compound (C). Therefore, in the case where the solid electrolyte composition of the present invention contains a plurality of compounds corresponding to the compound (C) and the compound (D), 1 (1) of the compounds are distributed as the compound (C), and the remaining compounds are distributed as the compound (D).

In the present invention, the polymerizable group capable of undergoing polymerization reaction with the polymerizable group of the compound (C) means a polymerizable group which exhibits a characteristic that the polymerizable group of the compound (C) does not undergo polymerization reaction under the preparation conditions (mixing conditions) of the solid electrolyte composition described later, but does undergo polymerization reaction under the heating conditions described later. The term "not reacting with the polymerization-reactive group" means that the polymer-reactive group may be partially reacted (10 mass% or less) unless the film forming property, handling property, etc. of the solid electrolyte composition are impaired.

The polymerization-reactive group of the compound (C) and the polymerization-reactive group of the compound (D) have a property of being capable of undergoing a mutual polymerization reaction, and thus the mutual polymerization reaction is initiated under a heating condition described later. Thus, as a reactant of the compound (C) and the compound (D), a crosslinked polymer of the compound (C) component and the compound (D) component is obtained.

The polymerization-reactive groups of the compound (C) and the compound (D) may be present in the molecular structure of each compound, or may be present in the interior or at the end of the molecular structure. From the viewpoint of reactivity, it is preferably present at the end.

The polymerization-reactive groups of the compound (C) and the compound (D) are not particularly limited as long as they are the above-mentioned polymerization-reactive groups. The polymerization-reactive group is preferably 1 of the polymerization-reactive groups capable of undergoing a condensation reaction or an addition reaction, and is preferable from the viewpoint that the polymerization-reactive groups capable of undergoing an addition reaction do not generate by-products based on the reaction.

The polymerization-reactive groups each of the compound (C) and the compound (D) preferably are selected from 1 kind of polymerization-reactive groups in the following polymerization-reactive group (a).

< group (a) >, a polymerization-reactive group

Hydroxy, amino, carboxyl, alkoxycarbonyl, haloformyl (-C (=) -X: X represents halogen atom), sulfo, carbamoyl, formyl, isocyanate, oxetanyl, epoxy, dicarboxylic anhydride, silyl, alkynyl, alkenyl, bromo, chloro, iodo, diazo (= N) ₂ 、-N ⁺ ＝N ^- ) Azido (-N) ₃ ) Oxidizing nitrile groups (-C.ident.N) ⁺ -O ^- )

Here, the amino group has the same meaning as the amino group in the substituent T described below, and is preferably an unsubstituted amino group. The alkoxycarbonyl group includes an aryloxycarbonyl group in addition to the alkoxycarbonyl group in the substituent T described below. Silyl groups include alkylsilyl, arylsilyl, alkoxysilyl, aryloxysilyl groups and the like among the substituents T described below. Alkynyl and alkenyl are each as defined for alkynyl or alkenyl in substituent T below.

Among them, hydroxyl group, amino group, carboxyl group, haloformyl group, isocyanate group, oxetanyl group, epoxy group, dicarboxylic anhydride group, silyl group, alkynyl group, alkenyl group, azide group or nitrile oxide group is more preferable, and amino group, oxetanyl group, epoxy group, carboxyl group, alkynyl group, azide group or nitrile oxide group is further preferable.

The polymerization-reactive groups of the compound (C) and the compound (D) can be appropriately protected by a protecting group which is generally used.

The combination of the polymerization-reactive groups of the compound (C) and the polymerization-reactive groups of the compound (D) is not particularly limited as long as the above reaction is not performed under the mixing conditions described later, but is performed in the heating step described later, and is determined in consideration of the combination of the polymerization-reactive groups, the number of stages, the magnitude of steric hindrance, and the like. As the combination of the polymerization-reactive groups, for example, the combinations CA to CC of the polymerization-reactive group (I) and the polymerization-reactive group (II) shown in the following Table 1 are preferable.

In each of the combinations CA to CC shown in table 1, when a plurality of polymerization reactive groups are described in the column of the polymerization reactive group (I) or the column of the polymerization reactive group (II), the combination of the polymerization reactive groups is set to be a combination of one polymerization reactive group arbitrarily selected from the polymerization reactive groups described in each column.

In each of the combinations CA to CC shown in table 1 below, the polymerization-reactive group of the compound (C) may be any selected from the group consisting of the polymerization-reactive group (I) and the polymerization-reactive group (II), and is preferably a group selected from the group consisting of the polymerization-reactive group (I). Among the polymerization reactive groups (I) and (II) of each combination shown in table 1, an underlined polymerization reactive group is preferable.

TABLE 1

Among the above, the combination of the polymerization-reactive groups is more preferably any one of the combinations (C1) to (C9) shown below, and further preferably any one of the combinations (C3), (C4), (C6) to (C8). The polymerization-reactive group of the compound (C) is not particularly limited in each of the combinations (C1) to (C9) shown below, and is preferably a polymerization-reactive group described on the left side.

< combination of polymeric reactive groups >

The number of the polymerization-reactive groups of the compound (C) is not particularly limited as long as it is 3 or more. As long as the compound (C) has 3 or more polymerization-reactive groups, the compound (D) has only 2 polymerization-reactive groups, a branched structure can be formed in the reactant of the compound (C) and the compound (D), and a high film strength can be imparted to the solid electrolyte-containing sheet. The number of the polymerization-reactive groups is preferably 3 to 100, more preferably 3 to 6.

The number of the polymerization-reactive groups of the compound (D) is not particularly limited as long as it is 2 or more, and preferably 3 or more. As long as the compound (D) has 3 or more polymerization-reactive groups, not only a branched structure but also a three-dimensional network structure can be constructed in the reactant of the compound (C) and the compound (D), and a higher film strength can be imparted to the solid electrolyte-containing sheet. The number of the polymerization-reactive groups is preferably 100 or less, more preferably 6 or less.

The basic skeleton of the compound (C) and the compound (D) having the above-mentioned polymerization-reactive group is not particularly limited as long as it is a skeleton having 2 or more polymerization-reactive groups attached thereto, and can be appropriately selected.

The compound (C) and the compound (D) may be low-molecular compounds or oligomers or polymers. In the case of the low molecular compound, the molecular weight thereof is preferably 1000 or less, more preferably 50 to 800, and still more preferably 100 to 300. In the case of oligomers or polymers, the molecular weight means the mass average molecular weight.

As the compound (C), a compound represented by the following formula (b-12) is preferable.

[ chemical formula 6]

Wherein R is ^b2 The meaning of the polymerizable reactive group is preferably the same as that of the polymerizable reactive group capable of undergoing a condensation reaction or an addition reaction, and preferable groups are also the same.

na represents the number of polymeric reactive groups. na is not particularly limited as long as it is an integer of 3 or more, but is preferably an integer of 3 to 100, more preferably 3 to 6.

Ra represents a na-valent linking group. As the linking group that Ra can employ, as long as the valence is 3 or more, a group having a valence of na among linking groups composed of each of the following linking groups or a combination of these linking groups is preferably selected.

< linking group >

An alkane linking group (preferably an alkanetriyl group in the case of a valence of 1 to 30, for example, a cycloalkane linking group in the case of a valence of 3), a cycloalkane linking group (preferably an cycloalkane triyl group in the case of a valence of 3 to 12, for example), an aryl linking group (preferably an aryltriyl group in the case of a valence of 6 to 24, for example, a valence of 3), a heteroaryl linking group (preferably an aryltriyl group in the case of a valence of 3 to 12, for example, a heteroaryltriyl group), an oxy group (-O-), a thioether group (-S-), a phosphino group (-PR-); R is a bond, a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, a silylene group (-Si (R) ^S1 )(R ^S2 )-：R ^S1 、R ^S2 Is a bond, a hydrogen atom or an alkyl group having 1 to 6 carbon atoms), a carbonyl group, an imino group (-NR) ^Nb -：R ^Nb Is a bond, a hydrogen atom or an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms)

The heteroaryl ring forming the heteroaryl linking group contains at least 1 or more heteroatoms (e.g., nitrogen atom, oxygen atom, sulfur atom) as atoms constituting the ring, preferably a 5-membered ring or a 6-membered ring or a condensed ring of these.

Among them, the above-mentioned alkane linking group or the above-mentioned aryl linking group, or the above-mentioned alkane linking group, the above-mentioned aryl linking group, and a linking group composed of a combination of an oxo group and a carbonyl group are preferable. In the case of combination, 2 to 5 linking groups are preferably combined, and 2 linking groups are more preferably combined.

As the compound (D), a compound represented by the above formula (b-12) is preferable.

Wherein na in the formula (b-12) is an integer of 2 or more, not particularly limited, and is preferably an integer of 2 to 100, more preferably 2 to 6.

Further, ra in the formula (b-12) is a linking group having a valence of 2 or more, and is preferably an alkane linking group having 1 to 30 carbon atoms (alkylene group when the valence is 2), a cycloalkane linking group having 3 to 12 carbon atoms (cycloalkylene group when the valence is 2), an aryl linking group having 6 to 24 carbon atoms (arylene group when the valence is 2), a heteroaryl linking group having 3 to 12 carbon atoms (heteroarylene group when the valence is 2), an oxygen group, a thioether group, the phosphine group, the silylene group, a carbonyl group, the imino group, or a combination of these. Among them, an alkane linking group having 1 to 30 carbon atoms, an aryl linking group having 6 to 24 carbon atoms, an oxy group, a carbonyl group, or a combination of these are preferable. In the case of combination, 2 to 5 linking groups are preferably combined, and 2 linking groups are more preferably combined.

Specific examples of the compound (C) and the compound (D) are shown below, but in the present invention, the compound (C) and the compound (D) are not limited to these.

Specific examples of the compound (C) having 3 or more polymerization-reactive groups and the compound (D) having 2 or more polymerization-reactive groups are shown below. Accordingly, trimethylolpropane is a specific example of the compound (C) and the compound (D), and ethylene glycol is a specific example of the compound (D).

[ chemical formula 7]

The compound (C) and the compound (D) may be polymers synthesized by a usual method or commercially available products may be used.

Examples of the substituent T include the following groups.

Examples thereof include an alkyl group (preferably having 1 to 20 carbon atoms), an alkenyl group (preferably having 2 to 20 carbon atoms), an alkynyl group (preferably having 2 to 20 carbon atoms), a cycloalkyl group (preferably having 3 to 20 carbon atoms), a cycloalkyl group (preferably having 2 to 20 carbon atoms), an aryl group (preferably having 6 to 26 carbon atoms), an aralkyl group (preferably having 7 to 23 carbon atoms), a heterocyclic group (preferably having 2 to 20 carbon atoms), a heterocyclic group preferably having a 5-or 6-membered ring having at least 1 oxygen atom, sulfur atom or nitrogen atom), an alkoxy group (preferably having 1 to 20 carbon atoms), an aryloxy group (preferably having 6 to 26 carbon atoms), and an alkoxycarbonyl group (preferably having 2 to 20 carbon atoms) and an aryloxycarbonyl group (preferably having 2 to 26 carbon atoms) 6 to 26 atoms), amino group (preferably amino group, alkylamino group or arylamino group having 0 to 20 carbon atoms). ) The sulfamoyl group (preferably having 0 to 20 carbon atoms), the acyl group (preferably having 1 to 20 carbon atoms), and the aroyl group (preferably having 7 to 23 carbon atoms). Wherein, in the present invention, the term "acyl" is generally meant to include aroyl. ) An acyloxy group (preferably having 1 to 20 carbon atoms), an aralkoxy group (preferably having 7 to 23 carbon atoms). Wherein, in the present invention, the term "acyloxy" is generally meant to include an aralkoxy group. ) Carbamoyl (preferably 1 to 20 carbon atoms), amido (preferably 1 to 20 carbon atoms), alkylthio (preferably 1 to 20 carbon atoms), arylthio (preferably 6 to 26 carbon atoms), alkylsulfonyl (preferably 1 to 20 carbon atoms), arylsulfonyl (preferably 6 to 22 carbon atoms), alkylsilyl (preferably 1 to 20 carbon atoms), arylsilyl (preferably 6 to 42 carbon atoms), alkoxysilyl (preferably 1 to 20 carbon atoms), aryloxy silyl (preferably 6 to 42 carbon atoms), phosphoryl (preferably 0 to 20 carbon atoms), for example, -OP (=O) (R ^P ) ₂ ) A phosphono group (preferably a phosphono group having 0 to 20 carbon atoms, for example, -P (=O) (R) ^P ) ₂ ) Phosphinyl (preferably phosphinyl having 0 to 20 carbon atoms, e.g., -P (R) ^P ) ₂ ) (meth) acryl, (meth) acryloyloxy, (meth) acryloimido ((meth) acrylamido), hydroxyl, sulfanyl, carboxyl, phosphate, phosphonate, sulfonate, cyano, halogen atoms (e.g., fluorine atom, chlorine atom, bromine atom, iodine atom). R is R ^P Is a hydrogen atom, a hydroxyl group or a substituent (preferably a group selected from the substituents T).

Further, the substituent T may be further substituted with respect to each of the substituents listed for the substituent T.

The compound, substituent, linking group and the like include alkyl, alkylene, alkenyl, alkenylene, alkynyl, alkynylene and the like, and these may be cyclic or chain-like, and may be straight or branched, and may be substituted or unsubstituted as described above.

Reactants-

As described above, the reactant (crosslinked polymer) obtained by polymerizing the compound (C) and the compound (D) is a compound contained in the solid electrolyte-containing sheet of the present invention, and is described herein.

The reactant is a compound (low molecular compound, oligomer or polymer) in which the polymerization-reactive groups of the respective compounds react with each other by the condensation reaction or the addition reaction. The reactant is a compound that does not normally exhibit ionic conductivity of a metal belonging to group 1 or group 2 of the periodic table. Here, the term "ion conductivity" is not shown, but includes a case where the ion conductivity is shown so far as it is smaller than the ion conductivity required for the all-solid-state secondary battery (so long as it does not function as an ion conductor).

The reactant preferably has a polymer compound derived from a constituent component of the compound (C) (also referred to as a compound (C) component) and a constituent component of the compound (D) (also referred to as a compound (D) component), and also referred to as a crosslinked polymer of the compound (C) component and the compound (D) component. The reactant has a crosslinked structure (bond) formed by reacting the polymerization-reactive group of the compound (C) with the polymerization-reactive group of the compound (D). The crosslinked structure is determined by the combination of the polymeric reactive groups of each compound. Examples of the crosslinked structure based on the preferable combinations (C1) to (C9) of the above-mentioned polymerization-reactive groups are described in the following table 2, for example, but the present invention is not limited to these.

TABLE 2

Examples of the resin having the above-mentioned crosslinked structure include epoxy resin, urethane resin, polyester resin, urea resin, polyamide resin, polyimide resin, polysiloxane, triazole ring-containing polymer based on an addition cyclization reaction of azide group and alkynyl group (Huisgen cyclization reaction), isoxazoline ring-containing polymer based on an addition cyclization reaction of nitrile oxide group and alkynyl group, 1-amino-2-hydroxyvinyl structure-containing polymer based on an addition reaction of amino group and epoxy group (also referred to as 1, 2-amino alcohol structure), and 1-amino-3-hydroxytrimethylene structure-containing polymer based on an addition reaction of amino group and oxetanyl group (1, 3-amino alcohol structure).

The reactant has the above-mentioned crosslinked structure according to the number of polymerization-reactive groups and the like which the compound (C) and the compound (D) have, respectively.

The condensation reaction and the addition reaction are carried out at normal temperature or under heating, respectively, in the presence of a catalyst or the like as required. The details of the production of the solid electrolyte-containing sheet will be described later.

The contents of the polymer (a), the electrolyte salt (B), the compound (C), and the compound (D) in the solid electrolyte composition are not particularly limited, and the following contents are preferably satisfied.

The content of the polymer (a) in the solid component of the solid electrolyte composition of the present invention is preferably 10 mass% or more, more preferably 30 mass% or more, and particularly preferably 50 mass% or more. The upper limit is preferably 90 mass% or less, more preferably 80 mass% or less, and particularly preferably 70 mass% or less.

The content of the electrolyte salt (B) in the solid component of the solid electrolyte composition of the present invention is preferably 5 mass% or more, more preferably 10 mass% or more, and particularly preferably 20 mass% or more. The upper limit is preferably 60 mass% or less, more preferably 50 mass% or less, and particularly preferably 40 mass% or less.

The content of the compound (C) in the solid component of the solid electrolyte composition of the present invention is preferably 0.5 mass% or more, more preferably 1 mass% or more, and particularly preferably 2 mass% or more. The upper limit is preferably 40 mass% or less, more preferably 30 mass% or less, and particularly preferably 20 mass% or less.

The content of the compound (D) in the solid component of the solid electrolyte composition of the present invention is preferably 0.5 mass% or more, more preferably 1 mass% or more, and particularly preferably 2 mass% or more. The upper limit is preferably 40 mass% or less, more preferably 30 mass% or less, and particularly preferably 20 mass% or less.

The solid component (solid content) of the solid electrolyte composition of the present invention is a component that does not volatilize or evaporate and disappears when subjected to a drying treatment at 100 ℃ for 6 hours under a nitrogen atmosphere of 1 atm. Typically, the components contained in the solid electrolyte composition of the present invention are components other than the solvent (G) described below.

When the solid electrolyte composition contains a plurality of specific components, the content of the components is set to be the total content of the plurality of components.

In the case where the solid electrolyte composition contains the reactants of the compound (C) and the compound (D), the contents of the compound (C) and the compound (D) forming the reactants are also calculated.

The contents of the polymer (a), the electrolyte salt (B), the compound (C) and the compound (D) in the solid electrolyte composition preferably satisfy the mass ratio of the polymer (a) to the electrolyte salt (B) to the compound (C) to the compound (D) =1:0.05 to 2.50:0.04 to 2:0.04 to 2. When the mass ratio of the content is satisfied, the film strength and the ion conductivity can be exhibited at a higher level when a sheet containing a solid electrolyte is produced.

The content of the polymer (a) and the electrolyte salt (B) is preferably the polymer (a): the electrolyte salt (B) =1:0.05 to 2.50, more preferably 1:0.3 to 1, in terms of mass ratio.

The mass ratio of the polymer (A) to the total of the compound (C) and the compound (D) is preferably 1:0.08 to 4, more preferably 1:0.1 to 1.4, still more preferably 1:0.12 to 0.8, and particularly preferably 1:0.15 to 0.4.

In the solid electrolyte composition of the present invention, the compound (C) and the compound (D) are preferably contained in the above amounts, and in addition to the above mass ratio, the following formula (R) is also preferred ^G ) Ratio R of defined polymerization-reactive groups ^G Greater than 0.8 and less than 1.2. Regarding the compound (C) and the compound (D), if the number and the content of the polymerization-reactive groups are set so as to satisfy the ratio R ^G The number of polymerization-reactive groups of each of the compound (C) and the compound (D)Approximately, and the reaction of these polymeric reactive groups proceeds more uniformly. This makes the cross-linked structure of the reactant more uniform, and can further improve the film strength without reducing the ionic conductivity of the solid electrolyte-containing sheet. Ratio R of polymerization-reactive groups in solid electrolyte composition ^G More preferably 0.9 to 1.1.

(R) ^G )：

R ^G Number of polymerization-reactive groups in = [ Compound (C) 1 molecule ]]Number of polymerization-reactive groups in molecule of/(D) 1. Times. Content of Compound (D) in solid electrolyte composition]

(R) ^G ) The contents of the compound (C) and the compound (D) in the solid electrolyte composition are set to molar equivalent values.

(R) ^G ) In the case where the solid electrolyte composition contains a plurality of compounds (D) [ the number of the polymerization-reactive groups in the molecules of the compound (D) 1 ]]The total amount of the product of the number of the polymerization-reactive groups in each molecule of the compound (D) 1 and the content (mol) of each compound (D) is set.

The number and content of the polymerization-reactive groups of the compound (C) and the compound (D) can be calculated from analysis of nuclear magnetic resonance spectroscopy (NMR), liquid chromatography, gas chromatography, or the like of the solid electrolyte composition, or from the amount of the compound used in preparing the solid electrolyte composition.

Inorganic solid electrolyte (E) >)

The solid electrolyte composition of the present invention may contain an inorganic solid electrolyte (E). If the solid electrolyte composition contains an inorganic solid electrolyte, the ion conductivity of the solid electrolyte-containing sheet obtained from the solid electrolyte composition and the ion conductivity of the all-solid-state secondary battery provided with the solid electrolyte-containing sheet can be further improved.

The inorganic solid electrolyte is an inorganic solid electrolyte, and the solid electrolyte is a solid electrolyte capable of moving ions therein. Since it does not contain as the mainThe organic substance of the ion conductive material is clearly distinguished from an organic solid electrolyte (such as the above-mentioned ion conductor using polyethylene oxide (PEO) or the like) and an organic electrolyte salt typified by lithium bis (trifluoromethanesulfonyl) imide (LiTFSI) or the like. Further, since the inorganic solid electrolyte is solid in a stable state, it is not usually dissociated or dissociated into cations and anions. At this point, an inorganic electrolyte salt (LiPF) which is also dissociated with cations or anions or is dissociated in an electrolyte or a polymer ₆ 、LiBF ₄ LiFSI, liCl, etc.) are clearly distinguished. The inorganic solid electrolyte is not particularly limited as long as it has ion conductivity of a metal belonging to group 1 or group 2 of the periodic table, and generally does not have electron conductivity.

In the present invention, the inorganic solid electrolyte has ion conductivity of a metal belonging to group 1 or group 2 of the periodic table. The above inorganic solid electrolyte can be used by appropriately selecting a solid electrolyte material suitable for use in such a product. As typical examples of the inorganic solid electrolyte, (i) sulfide-based inorganic solid electrolyte and (ii) oxide-based inorganic solid electrolyte can be cited. In the present invention, the inorganic solid electrolyte is preferably a sulfide-based inorganic solid electrolyte from the viewpoints of ion conductivity, flexibility, and the like. In addition, in the case where the solid electrolyte composition of the present invention contains an active material, a more favorable interface can be formed between the sulfide-based inorganic solid electrolyte and the active material, and therefore, it is preferable.

(i) Sulfide-based inorganic solid electrolyte

The sulfide-based inorganic solid electrolyte is preferably a compound containing a sulfur atom (S), having ion conductivity of a metal belonging to group 1 or group 2 of the periodic table, and having electronic insulation. The sulfide-based inorganic solid electrolyte preferably contains at least Li, S, and P as elements and has lithium ion conductivity, but may contain other elements than Li, S, and P depending on the purpose or case.

Since the sulfide-based inorganic solid electrolyte is more excellent in ion conductivity, the solid electrolyte composition of the present invention preferably contains a lithium ion-conductive inorganic solid electrolyte satisfying the composition represented by the following formula (1).

L _a1 M _b1 P _c1 S _d1 A _e1 (1)

Wherein L represents an element selected from Li, na and K, preferably Li. M represents an element selected from B, zn, sn, si, cu, ga, sb, al and Ge. A represents an element selected from the group consisting of I, br, cl and F. a1 to e1 represent the composition ratio of each element, and a1:b1:c1:d1:e1 satisfies 1 to 12:0 to 5:1:2 to 12:0 to 10. a1 is more preferably 1 to 9, and still more preferably 1.5 to 7.5. b1 is preferably 0 to 3, more preferably 0 to 1. d1 is more preferably 2.5 to 10, still more preferably 3.0 to 8.5. e1 is more preferably 0 to 5, still more preferably 0 to 3.

The composition ratio of each element can be controlled by adjusting the blending amount of the raw material compound in the production of the sulfide-based inorganic solid electrolyte, as described below.

The sulfide-based inorganic solid electrolyte may be amorphous (glass), may be crystallized (glass-ceramic), or may be partially crystallized. For example, li-P-S glass containing Li, P and S or Li-P-S glass ceramic containing Li, P and S can be used.

The sulfide-based inorganic solid electrolyte can be produced by using, for example, lithium sulfide (Li ₂ S), phosphorus sulfide (e.g. phosphorus pentasulfide (P) ₂ S ₅ ) Monomeric phosphorus, monomeric sulfur, sodium sulfide, hydrogen sulfide, lithium halides (e.g., liI, liBr, liCl), sulfides of the elements represented by M above (e.g., siS) ₂ 、SnS、GeS ₂ ) Is produced by reacting at least 2 or more raw materials.

Li-P-S glass and Li in Li-P-S glass ceramic ₂ S and P ₂ S ₅ At a ratio of Li ₂ S:P ₂ S ₅ The molar ratio of (2) is preferably 60:40 to 90:10, more preferably 68:32 to 78:22. By mixing Li with ₂ S and P ₂ S ₅ The ratio (c) is set to this range, and the lithium ion conductivity can be improved. Specifically, the lithium ion conductivity can be preferably set to 1×10 ^-4 S/cm or more, more preferably 1X 10 ^-3 S/cm or more. There is no particular upper limit, but in practice 1X 10 ^-1 S/cm or less.

As specific examples of the sulfide-based inorganic solid electrolyte, combinations of raw materials are exemplified as follows. For example, li ₂ S-P ₂ S ₅ 、Li ₂ S-P ₂ S ₅ -LiCl、Li ₂ S-P ₂ S ₅ -H ₂ S、Li ₂ S-P ₂ S ₅ -H ₂ S-LiCl、Li ₂ S-LiI-P ₂ S ₅ 、Li ₂ S-LiI-Li ₂ O-P ₂ S ₅ 、Li ₂ S-LiBr-P ₂ S ₅ 、Li ₂ S-Li ₂ O-P ₂ S ₅ 、Li ₂ S-Li ₃ PO ₄ -P ₂ S ₅ 、Li ₂ S-P ₂ S ₅ -P ₂ O ₅ 、Li ₂ S-P ₂ S ₅ -SiS ₂ 、Li ₂ S-P ₂ S ₅ -SiS ₂ -LiCl、Li ₂ S-P ₂ S ₅ -SnS、Li ₂ S-P ₂ S ₅ -Al ₂ S ₃ 、Li ₂ S-GeS ₂ 、Li ₂ S-GeS ₂ -ZnS、Li ₂ S-Ga ₂ S ₃ 、Li ₂ S-GeS ₂ -Ga ₂ S ₃ 、Li ₂ S-GeS ₂ -P ₂ S ₅ 、Li ₂ S-GeS ₂ -Sb ₂ S ₅ 、Li ₂ S-GeS ₂ -Al ₂ S ₃ 、Li ₂ S-SiS ₂ 、Li ₂ S-Al ₂ S ₃ 、Li ₂ S-SiS ₂ -Al ₂ S ₃ 、Li ₂ S-SiS ₂ -P ₂ S ₅ 、Li ₂ S-SiS ₂ -P ₂ S ₅ -LiI、Li ₂ S-SiS ₂ -LiI、Li ₂ S-SiS ₂ -Li ₄ SiO ₄ 、Li ₂ S-SiS ₂ -Li ₃ PO ₄ 、Li ₁₀ GeP ₂ S ₁₂ Etc. The mixing ratio of the raw materials is not limited. As a method for synthesizing a sulfide-based inorganic solid electrolyte material using such a raw material composition, for example, an amorphous method can be cited. As amorphousExamples of the homogenization method include a mechanical polishing method, a solution method, and a melt quenching method. This is because the process can be performed at normal temperature, and the manufacturing process can be simplified.

(ii) Oxide-based inorganic solid electrolyte

The oxide-based inorganic solid electrolyte is preferably a compound containing an oxygen atom (O), having ion conductivity of a metal belonging to group 1 or group 2 of the periodic table, and having electronic insulation.

Specific examples of the compound include Li _xa La _ya TiO ₃ 〔xa＝0.3～0.7、ya＝0.3～0.7〕(LLT)、Li _xb La _yb Zr _zb M ^bb _mb O _nb (M ^bb Is at least 1 element in Al, mg, ca, sr, V, nb, ta, ti, ge, in, sn, xb is more than or equal to 5 and less than or equal to 10, yb is more than or equal to 1 and less than or equal to 4, zb is more than or equal to 1 and less than or equal to 4, mb is more than or equal to 0 and less than or equal to 2, nb is more than or equal to 5 and less than or equal to 20. ) Li (Li) _xc B _yc M ^cc _zc O _nc (M ^cc Is at least 1 element in C, S, al, si, ga, ge, in, sn, xc is more than or equal to 0 and less than or equal to 5, yc is more than or equal to 0 and less than or equal to 1, zc is more than or equal to 0 and less than or equal to 1, nc is more than or equal to 0 and less than or equal to 6. ) Li (Li) _xd (Al，Ga) _yd (Ti，Ge) _zd Si _ad P _md O _nd (wherein, xd is more than or equal to 1 and less than or equal to 3, yd is more than or equal to 0 and less than or equal to 1, zd is more than or equal to 0 and less than or equal to 2, ad is more than or equal to 0 and less than or equal to 1, md is more than or equal to 1 and less than or equal to 7, nd is more than or equal to 3 and less than or equal to 13), li _(3-2xe) M ^ee _xe D ^ee O (xe represents a number of 0 to 0.1 inclusive, M) ^ee Representing a metal atom of valence 2. D (D) ^ee Represents a halogen atom or a combination of 2 or more halogen atoms. ) Li (Li) _xf Si _yf O _zf (1≤xf≤5、0＜yf≤3、1≤zf≤10)、Li _xg S _yg O _zg (1≤xg≤3、0＜yg≤2、1≤zg≤10)、Li ₃ BO ₃ -Li ₂ SO ₄ 、Li ₂ O-B ₂ O ₃ -P ₂ O ₅ 、Li ₂ O-SiO ₂ 、Li ₆ BaLa ₂ Ta ₂ O ₁₂ 、Li ₃ PO _(4-3/2w) N _w (w satisfies w <)1) Having LISICON (Lithium super ionic conductor: lithium super ion conductor) crystal structure of Li _3.5 Zn _0.25 GeO ₄ La having perovskite-type crystal structure _0.55 Li _0.35 TiO ₃ Li (lithium ion battery) _0.33 La _0.55 TiO ₃ LiTi with NASICON (Natrium super ionic conductor: sodium super-ion conductor) crystal structure ₂ P ₃ O ₁₂ 、Li _1+xh+yh (Al，Ga) _xh (Ti，Ge) _2-xh Si _yh P _3-yh O ₁₂ (wherein 0.ltoreq.xh.ltoreq.1, 0.ltoreq.yh.ltoreq.1), li having garnet-type crystal structure ₇ La ₃ Zr ₂ O ₁₂ (LLZ), and the like. Further, phosphorus compounds containing Li, P and O are also preferable. For example, lithium phosphate (Li ₃ PO ₄ ) LiPON, liPOD in which part of oxygen in lithium phosphate is replaced with nitrogen ¹ (D ¹ At least 1 selected from Ti, V, cr, mn, fe, co, ni, cu, zr, nb, mo, ru, ag, ta, W, pt, au and the like), and the like. In addition, liA can also be preferably used ¹ ON(A ¹ At least 1 selected from Si, B, ge, al, C, ga and the like), and the like.

The volume average particle diameter of the inorganic solid electrolyte is not particularly limited, but is preferably 0.01 μm or more, and more preferably 0.1 μm or more. The upper limit is preferably 100 μm or less, more preferably 50 μm or less.

When the solid electrolyte composition contains an inorganic solid electrolyte, the content of the inorganic solid electrolyte in the solid electrolyte composition is preferably 1 mass% or more, more preferably 5 mass% or more, and particularly preferably 10 mass% or more, based on 100 mass% of the solid component, in consideration of the reduction in interfacial impedance and the maintenance of the reduced interfacial impedance when used in an all-solid secondary battery. The upper limit is preferably 97% by mass or less, more preferably 70% by mass or less, and particularly preferably 30% by mass or less, from the same viewpoint.

The inorganic solid electrolyte may be used alone or in combination of 1 or 2 or more.

< active substance (F) >)

The solid electrolyte composition of the present invention may contain an active material (F) capable of intercalating and deintercalating ions of a metal belonging to group 1 or group 2 of the periodic table.

The active material may be used without being particularly limited to those commonly used in all-solid-state secondary batteries, and examples thereof include positive electrode active materials and negative electrode active materials. The transition metal oxide serving as the positive electrode active material, or lithium titanate or graphite serving as the negative electrode active material is preferable.

Positive electrode active material

The positive electrode active material is preferably a material capable of reversibly intercalating and deintercalating lithium ions. The material is not particularly limited as long as it has the above-described characteristics, and examples thereof include elements capable of being combined with Li, such as transition metal oxides, organic substances, and sulfur, and combinations of sulfur and metals.

Among them, the positive electrode active material is preferably a transition metal oxide, more preferably a material having a transition metal element M ^a A transition metal oxide (1 or more elements selected from Co, ni, fe, mn, cu and V). The transition metal oxide may be mixed with the element M ^b (elements of group 1 (Ia), group 2 (IIa), al, ga, in, ge, sn, pb, sb, bi, si, P, B, etc. of the periodic Table other than lithium). As the mixing amount, it is preferable to use the transition metal element M ^a The amount (100 mol%) of (C) is 0 to 30mol%. More preferably in Li/M ^a Is synthesized by mixing them so that the molar ratio of the mixture is 0.3 to 2.2.

Specific examples of the transition metal oxide include (MA) a transition metal oxide having a layered rock salt type structure, (MB) a transition metal oxide having a spinel type structure, (MC) a lithium-containing transition metal phosphate compound, (MD) a lithium-containing transition metal halophosphoric acid compound, and (ME) a lithium-containing transition metal silicate compound. In the present invention, (MA) a transition metal oxide having a layered rock salt type structure or (MC) a lithium-containing transition metal phosphate compound is preferable.

Specific examples of transition metal oxides having a layered rock salt structure as (MA)Examples include LiCoO ₂ (lithium cobalt oxide [ LCO ]])、LiNiO ₂ Lithium nickel oxide LiNi _0.85 Co _0.10 Al _0.05 O ₂ (Nickel cobalt lithium aluminate [ NCA ]])、LiNi _1/3 Co _1/3 Mn _1/3 O ₂ (lithium Nickel manganese cobalt oxide [ NMC ]]) LiNi _0.5 Mn _0.5 O ₂ (lithium manganese nickelate).

As specific examples of (MB) the transition metal oxide having a spinel structure, liMn may be mentioned ₂ O ₄ (LMO)、LiCoMnO ₄ 、Li ₂ FeMn ₃ O ₈ 、Li ₂ CuMn ₃ O ₈ 、Li ₂ CrMn ₃ O ₈ Li (lithium ion battery) ₂ NiMn ₃ O ₈ 。

As the (MC) lithium-containing transition metal phosphate compound, for example, liFePO may be mentioned ₄ (lithium iron phosphate [ LFP ]]) Li (lithium ion battery) ₃ Fe ₂ (PO ₄ ) ₃ Isolibanum ferric phosphate salt and LiFeP ₂ O ₇ Isotophosphate iron species, liCoPO ₄ Cobalt isophosphate and Li ₃ V ₂ (PO ₄ ) ₃ And (lithium vanadium phosphate) and the like.

As the (MD) lithium-containing transition metal halophosphoric acid compound, for example, li ₂ FePO ₄ F and other ferric fluorophosphates, li ₂ MnPO ₄ F and other fluorophosphates of manganese and Li ₂ CoPO ₄ And F and other cobalt fluorophosphates.

As the (ME) lithium-containing transition metal silicate compound, for example, li ₂ FeSiO ₄ 、Li ₂ MnSiO ₄ Li (lithium ion battery) ₂ CoSiO ₄ Etc.

In the present invention, (MC) lithium-containing transition metal phosphate compound is preferable, olivine-type ferric phosphate salt is more preferable, and LFP is further preferable.

The shape of the positive electrode active material is not particularly limited, and is preferably in the form of particles. The volume average particle diameter (average particle diameter in terms of spheres) of the positive electrode active material is not particularly limited. For example, the thickness can be set to 0.1 to 50. Mu.m.

The positive electrode active material may be used alone in an amount of 1 or 2 or more.

When the solid electrolyte composition contains a positive electrode active material, the content of the positive electrode active material in the solid electrolyte composition is not particularly limited, but is preferably 10 to 95% by mass, more preferably 30 to 90% by mass, still more preferably 50 to 85% by mass, and particularly preferably 55 to 80% by mass, of the solid content of 100% by mass.

Negative electrode active material

The negative electrode active material is preferably a material capable of reversibly intercalating and deintercalating lithium ions. The material is not particularly limited as long as it has the above-mentioned characteristics, and examples thereof include carbonaceous materials, metal oxides such as tin oxide, silicon oxides, metal composite oxides, lithium alloys such as lithium single bodies and lithium aluminum alloys, and metals capable of forming alloys with lithium such as Sn, si, al and In. Among them, carbonaceous materials or metal composite oxides are preferably used from the viewpoint of reliability. Further, the metal composite oxide is preferably capable of occluding and releasing lithium. The material is not particularly limited, but from the viewpoint of high current density charge and discharge characteristics, it is preferable to contain titanium and/or lithium as constituent components.

The carbonaceous material used as the anode active material refers to a material substantially containing carbon. For example, carbon black such as petroleum pitch, graphite (e.g., natural graphite, vapor-grown graphite, etc.), and various synthetic resins such as PAN (polyacrylonitrile) resin and furfuryl alcohol resin can be used as carbonaceous materials. Examples of the carbon fiber include various carbon fibers such as PAN-based carbon fibers, cellulose-based carbon fibers, pitch-based carbon fibers, dehydrated PVA (polyvinyl alcohol) -based carbon fibers, lignin-based carbon fibers, glassy carbon fibers and activated carbon fibers, mesophase microspheres, graphite whiskers, and plate-like graphite.

As the metal oxide and the metal composite oxide which are suitable for the negative electrode active material, amorphous oxides are particularly preferable, and chalcogenides which are reaction products of metal elements and elements of group 16 of the periodic table are more preferably used. The amorphous material as used herein means a material having a broad scattering band having an apex in a region having a 2 theta value of 20 ° to 40 ° by an X-ray diffraction method using cukα rays, and may have a crystalline diffraction line.

Among the above-mentioned group of amorphous oxides and chalcogenides, amorphous oxides and chalcogenides of semi-metallic elements are more preferable, and oxides and chalcogenides containing 1 kind of element of groups 13 (IIIB) to 15 (VB) of the periodic table, al, ga, si, sn, ge, pb, sb and Bi alone or a combination of 2 or more kinds thereof are particularly preferable. Specific examples of the preferred amorphous oxide and chalcogenide include Ga ₂ O ₃ 、SiO、GeO、SnO、SnO ₂ 、PbO、PbO ₂ 、Pb ₂ O ₃ 、Pb ₂ O ₄ 、Pb ₃ O ₄ 、Sb ₂ O ₃ 、Sb ₂ O ₄ 、Sb ₂ O ₈ Bi ₂ O ₃ 、Sb ₂ O ₈ Si ₂ O ₃ 、Sb ₂ O ₅ 、Bi ₂ O ₃ 、Bi ₂ O ₄ 、SnSiO ₃ 、GeS、SnS、SnS ₂ 、PbS、PbS ₂ 、Sb ₂ S ₃ 、Sb ₂ S ₅ SnSiS ₃ . And these may be composite oxides with lithium oxide, for example Li ₂ SnO ₂ 。

The negative electrode active material may be used alone in an amount of 1 or 2 or more.

When the solid electrolyte composition contains the negative electrode active material, the content of the negative electrode active material in the solid electrolyte composition is not particularly limited, but is preferably 10 to 80 mass%, more preferably 20 to 80 mass%, of 100 mass% of the solid content.

The surface of the positive electrode active material and the negative electrode active material may be coated with different metal oxides. Examples of the surface coating agent include metal oxides containing Ti, nb, ta, W, zr, al, si and Li. Specifically, examples of the compound include spinel titanate, tantalum oxide, niobium oxide, and lithium niobate compound, and specifically, examples of the compound include Li ₄ Ti ₅ O ₁₂ 、Li ₂ Ti ₂ O ₅ 、LiTaO ₃ 、LiNbO ₃ 、LiAlO ₂ 、Li ₂ ZrO ₃ 、Li ₂ WO ₄ 、Li ₂ TiO ₃ 、Li ₂ B ₄ O ₇ 、Li ₃ PO ₄ 、Li ₂ MoO ₄ 、Li ₃ BO ₃ 、LiBO ₂ 、Li ₂ CO ₃ 、Li ₂ SiO ₃ 、SiO ₂ 、TiO ₂ 、ZrO ₂ 、Al ₂ O ₃ 、B ₂ O ₃ Etc.

The surface of the electrode containing the positive electrode active material or the negative electrode active material may be surface-treated with sulfur or phosphorus.

The surface of the particles of the positive electrode active material or the negative electrode active material may be subjected to surface treatment with actinic rays or an active gas (plasma or the like) before and after the surface coating.

< solvent (G) >)

The solid electrolyte composition of the present invention preferably contains a solvent (dispersion medium) capable of dissolving or dispersing the above components. The solvent (G) is not particularly limited as long as it is a solvent generally used in solid electrolyte compositions for all-solid secondary batteries. It is preferable to select a solvent having no group capable of reacting with the above-mentioned polymerization-reactive group of the compound (C) or the compound (D) at the time of preparation or storage of the solid electrolyte composition.

As such a solvent, the following solvents can be exemplified.

Examples of the alcohol compound solvents include methanol, ethanol, 1-propanol, 2-butanol, ethylene glycol, propylene glycol, 1, 6-hexanediol, 2-methyl-2, 4-pentanediol, 1, 3-butandiol, and 1, 4-butanediol.

Examples of the ether compound solvents include alkylene glycol (triethylene glycol, etc.), alkylene glycol monoalkyl ether (ethylene glycol monomethyl ether, etc.), alkylene glycol dialkyl ether (ethylene glycol dimethyl ether, etc.), dialkyl ether (diisopropyl ether, dibutyl ether, etc.), cyclic ether (tetrahydrofuran, dioxane (including 1,2-, 1,3-, and 1, 4-isomers), and the like.

Examples of the amide compound solvents include N, N-dimethylformamide, 1-methyl-2-pyrrolidone, 1, 3-dimethyl-2-imidazolidinone, 2-pyrrolidone, epsilon-caprolactam, formamide, N-methylformamide, acetamide, N-methylacetamide, N-dimethylacetamide, N-methylpropanamide, hexamethylphosphoric triamide.

Examples of the amine compound solvents include triethylamine, diisopropylethylamine, and tributylamine.

Examples of the ketone compound solvent include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and dibutyl ketone.

Examples of the aromatic compound solvent include benzene, toluene, xylene, and mesitylene.

Examples of the aliphatic solvent include hexane, heptane, cyclohexane, methylcyclohexane, octane, pentane, and cyclopentane.

Examples of the nitrile compound solvents include acetonitrile, propionitrile, butyronitrile, and isobutyronitrile.

The boiling point of the solvent at normal pressure (1 atm) is preferably 50℃or higher, more preferably 70℃or higher. The upper limit is preferably 250℃or less, more preferably 220℃or less, and still more preferably less than 100 ℃. The above solvents may be used alone or in combination of 1 or 2 or more.

In the present invention, an ether compound solvent, an amide compound solvent, a ketone compound solvent, or a nitrile compound solvent is preferable.

The solid electrolyte composition of the present invention preferably has a solid content concentration of 5 to 40 mass%, more preferably 8 to 30 mass%, and particularly preferably 10 to 20 mass%, from the viewpoints of film uniformity and drying speed of a coating film of the solid electrolyte composition.

In the present invention, the solid content of the solid electrolyte composition is as described above. The solid content concentration is generally set to a percentage of the mass of the above-described solvent to the total mass of the solid electrolyte composition subtracted from the total mass of the solid electrolyte composition.

< adhesive >

The solid electrolyte composition of the present invention may contain a binder. The binder may be contained in any form, and may be in the form of particles or irregular shapes in the solid electrolyte composition, the solid electrolyte-containing sheet, or the all-solid secondary battery, for example. The binder is preferably contained in the form of particles (polymer particles) composed of a resin. More preferably in the form of resin particles containing a macromer component.

In the case where the binder used in the present invention is a resin particle, the resin forming the resin particle is not particularly limited as long as it is an organic resin.

The binder is not particularly limited, and is preferably in the form of particles composed of, for example, the following resin.

Examples of the fluorine-containing resin include Polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), and a copolymer of polyvinylidene fluoride and hexafluoropropylene (PVdF-HFP).

Examples of the hydrocarbon thermoplastic resin include polyethylene, polypropylene, styrene Butadiene Rubber (SBR), hydrogenated Styrene Butadiene Rubber (HSBR), butene rubber, acrylonitrile butadiene rubber, polybutadiene, and polyisoprene.

Examples of the acrylic resin include various (meth) acrylic monomers, (meth) acrylamide monomers, and copolymers of monomers constituting these resins (preferably, copolymers of acrylic acid and methyl acrylate).

Also, copolymers with other vinyl monomers may be preferably used. For example, a copolymer of methyl (meth) acrylate and styrene, a copolymer of methyl (meth) acrylate and acrylonitrile, a copolymer of butyl (meth) acrylate and acrylonitrile and styrene can be cited. In the present invention, the copolymer may be any of a statistical copolymer and a periodic copolymer, and is preferably a block copolymer.

Examples of the other resin include polyurethane resin, polyurea resin, polyamide resin, polyimide resin, polyester resin, polyether resin, polycarbonate resin, and cellulose derivative resin.

Among them, fluorine-containing resins, hydrocarbon thermoplastic resins, acrylic resins, urethane resins, polycarbonate resins, and cellulose derivative resins are preferable, and acrylic resins and urethane resins are particularly preferable because the resins themselves have good flexibility and, when the inorganic solid electrolyte is contained, have good affinity with the inorganic solid electrolyte.

The binder may be synthesized or prepared by a usual method, or may be commercially available.

The binder may be used alone or in combination of 1 kind or 2 or more kinds.

When the solid electrolyte composition contains a binder, the content of the binder in the solid electrolyte composition is preferably 0.01 mass% or more, more preferably 0.1 mass% or more, and even more preferably 1 mass% or more, based on 100 mass% of the solid component, when the binder is used for the reduction of the interfacial impedance and the maintenance of the reduced interfacial impedance in the all-solid-state secondary battery. The upper limit is preferably 20 mass% or less, more preferably 10 mass% or less, and even more preferably 5 mass% or less, from the viewpoint of battery characteristics.

In the present invention, the mass ratio of the content of the inorganic solid electrolyte (E) and the active material (F) to the content of the binder [ (the content of the inorganic solid electrolyte (E + the content of the active material (F)/the content of the binder) ] is preferably in the range of 1,000 to 1. The ratio is more preferably 500 to 2, and still more preferably 100 to 10.

< conductive aid >)

The solid electrolyte composition of the present invention may also contain a conductive auxiliary agent. The conductive auxiliary is not particularly limited, and a conductive auxiliary generally known as a conductive auxiliary can be used. For example, the carbon material may be graphite such as natural graphite or artificial graphite, acetylene black, ketjen black (Ketjen black), carbon black such as furnace black, amorphous carbon such as needle coke, carbon fiber such as vapor grown carbon fiber or carbon nanotube, carbon material such as graphene or fullerene, metal powder such as copper or nickel, metal fiber, or conductive polymer such as polyaniline, polypyrrole, polythiophene, polyacetylene, or polyphenylene derivative. Further, 1 kind of these may be used, or 2 or more kinds may be used.

In the present invention, in the case where the active material and the conductive auxiliary agent are used together, among the above-mentioned conductive auxiliary agents, a material that does not undergo intercalation and deintercalation of ions of a metal belonging to group 1 or group 2 of the periodic table and does not exert the function of the active material is used as the conductive auxiliary agent when charging and discharging the battery. Therefore, among the conductive aids, a substance capable of functioning as an active substance in the active substance layer is classified as an active substance rather than a conductive aid when charging and discharging a battery. Whether or not to function as an active material when charging and discharging a battery is determined not uniquely but according to a combination with an active material.

(Ionic liquid)

The solid electrolyte composition of the present invention may contain an ionic liquid because the ionic conductivity of each layer constituting the solid electrolyte-containing sheet or the all-solid secondary battery is further improved. The ionic liquid is not particularly limited, and from the viewpoint of effectively improving ionic conductivity, the electrolyte salt (B) is preferable, and particularly, an electrolyte salt in which the lithium salt is dissolved. For example, the following cations and anions may be used in combination.

(i) Cations (cationic)

The cation is not particularly limited, and examples thereof include an imidazolium cation, a pyridinium cation, a piperidinium cation, a pyrrolidinium cation, a morpholinium cation, a phosphonium cation, and a quaternary ammonium cation. Wherein these cations have the following substituents.

As the cation, 1 kind of these cations may be used alone, or 2 or more kinds may be used in combination.

Preferably a quaternary ammonium cation, a piperidinium cation or a pyrrolidinium cation.

Examples of the substituent of the cation include an alkyl group (preferably an alkyl group having 1 to 8 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms), a hydroxyalkyl group (preferably a hydroxyalkyl group having 1 to 3 carbon atoms), an alkoxyalkyl group (preferably an alkoxyalkyl group having 2 to 8 carbon atoms, more preferably an alkoxyalkyl group having 2 to 4 carbon atoms), an ether group, an allyl group, an aminoalkyl group (preferably an aminoalkyl group having 1 to 8 carbon atoms, more preferably an aminoalkyl group having 1 to 4 carbon atoms), and an aryl group (preferably an aryl group having 6 to 12 carbon atoms, more preferably an aryl group having 6 to 8 carbon atoms). The substituents may form a cyclic structure in the form of containing a cationic site. The substituent may further have a substituent selected from the group consisting of substituent T. In addition, the above ether groups are used in combination with other substituents. Examples of such a substituent include an alkoxy group and an aryloxy group.

(ii) Anions (v-v)

Examples of the anion include, but are not particularly limited to, chloride ion, bromide ion, iodide ion, boron tetrafluoride ion, nitrate ion, dicyandiamide ion, acetate ion, ferric tetrachloride ion, bis (trifluoromethanesulfonyl) imide ion, bis (fluorosulfonyl) imide ion, bis (perfluorobutylmethanesulfonyl) imide ion, allylsulfonate ion, hexafluorophosphate ion, and trifluoromethanesulfonate ion.

As the anions, 1 kind of these anions may be used alone, or 2 or more kinds may be used in combination.

Boron tetrafluoride ion, bis (trifluoromethanesulfonyl) imide ion, bis (fluorosulfonyl) imide ion or hexafluorophosphate ion, dicyandiamide ion and allylsulfonate ion are preferred, and bis (trifluoromethanesulfonyl) imide ion or bis (fluorosulfonyl) imide ion and allylsulfonate ion are more preferred.

Examples of the ionic liquid include 1-allyl-3-ethylimidazolium bromide, 1-ethyl-3-methylimidazolium bromide, 1- (2-hydroxyethyl) -3-methylimidazolium bromide, 1- (2-methoxyethyl) -3-methylimidazolium bromide, 1-octyl-3-methylimidazolium chloride, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium tetrafluoroborate, 1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide, 1-ethyl-3-methylimidazolium bis (fluorosulfonyl) imide, 1-ethyl-3-methylimidazolium dicyandiamide, 1-butyl-1-methylpyrrolidine bis (trifluoromethylsulfonyl) imide, trimethylbutylammonium bis (trifluoromethylsulfonyl) imide, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium bis (trifluoromethylsulfonyl) imide (DEME), N-propyl-N-methylpyrrolidine bis (trifluoromethylsulfonyl) imide, and 1-methylpyrrolidine bis (trifluoromethylsulfonyl) imide, (2-Acrylethyl) trimethylammonium bis (trifluoromethanesulfonyl) imide, allyl 1-ethyl-1-methylpyrrolidine sulfonate, allyl 1-ethyl-3-methylimidazolium sulfonate, and trihexyltetradecylphosphonium chloride.

The content of the ionic liquid is preferably 0 part by mass or more, more preferably 1 part by mass or more, and most preferably 2 parts by mass or more, relative to 100 parts by mass of the ionic conductor. The upper limit is preferably 50 parts by mass or less, more preferably 20 parts by mass or less, and particularly preferably 10 parts by mass or less.

The mass ratio of the electrolyte salt (B) to the ionic liquid is preferably electrolyte salt (B) ionic liquid=1:20 to 20:1, more preferably 1:10 to 10:1, most preferably 1:7 to 2:1.

Preparation of solid electrolyte composition

The solid electrolyte composition of the present invention can be prepared by mixing the above-described components using, for example, various mixers. The above-mentioned components can be preferably prepared as a solution in a solvent or a slurry dispersed in a solvent.

The mixing device used for preparing the solid electrolyte composition is not particularly limited, and examples thereof include a ball mill, a bead mill, a planetary mixer, a blade mixer, a roll mill, a kneader, and a disc mill. The mixing conditions are set to conditions under which the compound (C) and the compound (D) do not undergo polymerization. The mixing temperature cannot be determined roughly according to the type or number of stages of the polymerization-reactive groups of the compound (C) and the compound (D), and is, for example, preferably 50 ℃ or lower, more preferably 30 ℃ or lower. The mixing environment is preferably a light shielding environment as needed. For example, in the case of using a ball mill, the mixture is preferably mixed at 150 to 700rpm (rotation per minute (revolutions per minute)) for 1 to 24 hours at the above-mentioned mixing temperature and mixing environment.

The above components may be added and mixed at the same time or separately.

In the case where the solid electrolyte composition of the present invention is stored after production, the solid electrolyte composition is stored under the condition that the compound (C) and the compound (D) do not undergo polymerization reaction. The storage temperature is preferably 50℃or lower, more preferably 30℃or lower, and particularly preferably 0℃or lower. And, it is preferably stored under light shielding.

[ sheet containing solid electrolyte ]

The solid electrolyte-containing sheet of the present invention has a layer composed of the solid electrolyte composition of the present invention.

The solid electrolyte-containing sheet can be obtained by forming a film of the solid electrolyte composition of the present invention, and specifically, the solid electrolyte composition of the present invention is a composition formed into a sheet by polymerizing a compound (C) and a compound (D) in the presence of a polymer (a) and an electrolyte salt (B). The solid electrolyte-containing sheet of the present invention contains a polymer (a), an electrolyte salt (B), a compound (C), and a reactant of a compound (D).

The meaning of the solid electrolyte-containing sheet of the present invention comprising the polymer (a) and the electrolyte salt (B) is the same as the meaning of the solid electrolyte composition comprising the polymer (a) and the electrolyte salt (B). The solid electrolyte-containing sheet contains the compound (C) and the compound (D) and contains the compound (C) or the compound (D) that is unreacted in addition to the reaction system in which the polymerization-reactive group of the compound (C) and the polymerization-reactive group of the compound (D) react. The reactants of compound (C) and compound (D) are as described above. The solid electrolyte-containing sheet of the present invention contains an ion conductor in a state of interacting with the above-mentioned reactant.

The solid electrolyte-containing sheet of the present invention can impart high ion conductivity and excellent durability to an all-solid-state secondary battery by being used as a negative electrode active material layer, a solid electrolyte layer, and/or a positive electrode active material layer. The details of the reason for this are described above.

The solid electrolyte-containing sheet of the present invention may contain the above-described components and the like preferably contained in the solid electrolyte composition, and for example, an inorganic solid electrolyte is preferably contained.

The content of each component in the solid electrolyte-containing sheet of the present invention is the same as the content in the solid content of the solid electrolyte composition. If the content of the reactant of the compound (C) and the compound (D) is the total content of the unreacted compound (C) and the compound (D), the total content of the compound (C) and the compound (D) in the solid content of the solid electrolyte composition is the same.

From the viewpoint of battery performance of the all-solid-state secondary battery, the solid electrolyte-containing sheet (layer composed of the solid electrolyte composition) preferably contains no volatile component, and may contain a volatile component if the content (residual amount) is 0.5 mass% or more and less than 20 mass% of the total mass of the solid electrolyte-containing sheet. The volatile component that can be contained in the solid electrolyte-containing sheet is a component that volatilizes in a vacuum (pressure of 10Pa or less) at 250 ℃ for 4 hours, and specifically, the unreacted compound (C) and the compound (D) may be exemplified as long as the component volatilizes under the above conditions in addition to the solvent (G). The content of the volatile component is preferably 0 to 10% by mass, more preferably 0.5 to 5% by mass, based on the total mass of the solid electrolyte-containing sheet.

The volatile content was measured by the method and conditions described in examples described later.

When the solid electrolyte-containing sheet contains the solvent (G), the content of the solvent may be within the above-mentioned range of the content of the volatile component, for example, within the range of 1 to 10000ppm of the total mass of the solid electrolyte-containing sheet.

The content ratio of the solvent (G) in the solid electrolyte-containing sheet of the present invention is the same as the measurement method of the volatile component.

The layer thickness of the solid electrolyte-containing sheet of the present invention is the same as the layer thickness of the solid electrolyte layer described in the all-solid-state secondary battery of the present invention, and is particularly preferably 20 to 150 μm.

The solid electrolyte-containing sheet of the present invention is suitable as a negative electrode active material layer, a solid electrolyte layer, and/or a positive electrode active material layer of an all-solid secondary battery.

The solid electrolyte-containing sheet of the present invention can be produced by: the solid electrolyte composition of the present invention is formed (coated and dried) on a substrate (other layers may be interposed) as needed, and the compound (C) and the compound (D) are polymerized in the presence of the polymer (a) and the electrolyte salt (B). Details will be described later.

The solid electrolyte-containing sheet of the present invention includes various modes depending on its use. For example, a sheet preferably used for a solid electrolyte layer (also referred to as a solid electrolyte sheet for an all-solid-state secondary battery), a sheet preferably used for an electrode or a laminate of an electrode and a solid electrolyte layer (an electrode sheet for an all-solid-state secondary battery), or the like can be cited. In the present invention, these various sheets are sometimes collectively referred to as sheets for all-solid-state secondary batteries.

The sheet for all-solid-state secondary batteries is a sheet having a solid electrolyte layer or an active material layer, and examples thereof include a sheet having a solid electrolyte layer or an active material layer on a substrate. In addition, the sheet for an all-solid-state secondary battery may not have a base material. The sheet for all-solid-state secondary batteries may have other layers as long as the sheet has a solid electrolyte layer or an active material layer, and the sheet containing an active material is classified into an electrode sheet for all-solid-state secondary batteries described later. Examples of the other layer include a protective layer and a current collector.

Examples of the solid electrolyte sheet for all-solid secondary batteries include a sheet having a solid electrolyte layer and a protective layer in this order on a base material, and a sheet having a solid electrolyte layer and a protective layer.

The substrate is not particularly limited as long as it can support the solid electrolyte layer and/or the active material layer, and examples thereof include a sheet (plate-like body) such as a material described in a current collector, an organic material, and an inorganic material. Examples of the organic material include various polymers, and specifically, polyethylene terephthalate, surface-treated (hydrophobicized) polyethylene terephthalate, polytetrafluoroethylene, polypropylene, polyethylene, cellulose, and the like. Examples of the inorganic material include glass and ceramics.

The layer thickness of the solid electrolyte layer of the solid electrolyte sheet for all-solid secondary batteries is the same as that described in the all-solid secondary battery of the present invention.

An electrode sheet for an all-solid-state secondary battery (also simply referred to as an "electrode sheet") is an electrode sheet having an active material layer on a metal foil as a current collector. The electrode sheet further includes a system including a current collector, an active material layer, and a solid electrolyte layer in this order, and a system including a current collector, an active material layer, a solid electrolyte layer, and an active material layer in this order. In the electrode sheet, the active material layer or the solid electrolyte layer can be formed from the solid electrolyte composition of the present invention.

The structure and layer thickness of each layer constituting the electrode sheet are the same as those described in the all-solid-state secondary battery of the present invention described later.

[ all-solid Secondary Battery ]

An all-solid-state secondary battery of the present invention comprises a positive electrode active material layer, a negative electrode active material layer, and a solid electrolyte layer between the positive electrode active material layer and the negative electrode active material layer. In this all-solid-state secondary battery, at least 1 layer (preferably all layers) of the positive electrode active material layer, the negative electrode active material layer, and the solid electrolyte layer is composed of a layer (solid electrolyte-containing sheet of the present invention) composed of the solid electrolyte composition of the present invention described later.

The positive electrode active material layer and the negative electrode active material layer each constitute a positive electrode or a negative electrode of the all-solid-state secondary battery separately (preferably together with a current collector). Thus, the all-solid-state secondary battery of the present invention can be referred to as a battery having a positive electrode, a negative electrode opposed to the positive electrode, and a solid electrolyte layer between the positive electrode and the negative electrode.

Hereinafter, a preferred embodiment of the present invention will be described with reference to fig. 1, but the present invention is not limited thereto.

Fig. 1 is a schematic cross-sectional view of an all-solid-state secondary battery (lithium ion secondary battery) according to a preferred embodiment of the present invention. The all-solid-state secondary battery 10 of the present embodiment has, in order from the negative electrode side, a negative electrode current collector 1, a negative electrode active material layer 2, a solid electrolyte layer 3, a positive electrode active material layer 4, and a positive electrode current collector 5. The layers are in contact with each other and are in a laminated structure. By adopting such a structure, electrons (e ^- ) And stores therein lithium ions (Li ⁺ ). On the other hand, lithium ions (Li ⁺ ) Returns to the positive electrode side and supplies electrons to the working site 6. In the illustrated example, a bulb is used at the working site 6, and the bulb is lighted by discharge.

When the all-solid-state secondary battery 10 having the layer structure shown in fig. 1 is placed in a 2032-type button cell case, the all-solid-state secondary battery 10 is referred to as an all-solid-state secondary battery sheet, and a battery produced by placing the all-solid-state secondary battery sheet in a 2032-type button cell case is sometimes referred to as an all-solid-state secondary battery for distinction.

Positive electrode active material layer, solid electrolyte layer, negative electrode active material layer >)

In the all-solid-state secondary battery 10, at least 1 layer among the anode active material layer 2, the solid electrolyte layer 3, and the cathode active material layer 4 is formed from the solid electrolyte-containing sheet of the present invention described above. It is preferable that at least 1 layer (preferably all layers) of the negative electrode active material layer 2, the solid electrolyte layer 3, and the positive electrode active material layer 4 contains an inorganic solid electrolyte. The layer containing an inorganic solid electrolyte can be formed using, for example, a solid electrolyte composition containing an inorganic solid electrolyte.

The layers other than the layers formed using the solid electrolyte composition of the present invention among the negative electrode active material layer 2, the solid electrolyte layer 3, and the positive electrode active material layer 4 can be formed using a solid electrolyte composition that is generally used. Examples of the usual solid electrolyte composition include compositions containing components other than the components (a) to (D) among the above components. The solid electrolyte layer 3 generally does not contain a positive electrode active material and/or a negative electrode active material.

The active material layer and/or the solid electrolyte layer formed using the solid electrolyte composition of the present invention is preferably the same as each component and the content thereof in the solid electrolyte-containing sheet unless the specific description of each component and the content thereof is given.

In the present invention, the positive electrode active material layer and the negative electrode active material layer are sometimes collectively referred to as an active material layer.

From the viewpoint of energy density, as one of preferred embodiments, the anode active material layer is a lithium layer. In this case, at least 1 layer of the solid electrolyte layer and the positive electrode active material layer is formed from the solid electrolyte-containing sheet of the present invention. In the present invention, the lithium layer includes a layer obtained by stacking or molding lithium powder, a lithium foil, and a lithium vapor deposition film.

The thicknesses of the negative electrode active material layer 2, the solid electrolyte layer 3, and the positive electrode active material layer 4 are not particularly limited. Considering the size of a general all-solid-state secondary battery, the lower limit of the thickness of each layer is preferably 3 μm or more, more preferably 10 μm or more. The upper limit is preferably 1,000 μm or less, more preferably less than 500 μm, and particularly preferably 150 μm or less. In the all-solid-state secondary battery of the present invention, the thickness of at least 1 layer of the anode active material layer, the solid electrolyte layer, and the cathode active material layer is preferably 50 μm or more and less than 500 μm.

< Current collector (Metal foil) >

The positive electrode current collector 5 and the negative electrode current collector 1 are preferably electron conductors.

In the present invention, either or both of the positive electrode current collector and the negative electrode current collector may be referred to simply as a current collector.

As a material for forming the positive electrode current collector, a material (a material for forming a thin film) of carbon, nickel, titanium or silver is preferably treated on the surface of aluminum or stainless steel, in addition to aluminum, aluminum alloy, stainless steel, nickel, titanium or the like, and among these, aluminum, stainless steel, aluminum alloy are more preferred.

As a material for forming the negative electrode current collector, in addition to aluminum, copper alloy, stainless steel, nickel, titanium, and the like, a material of carbon, nickel, titanium, or silver is preferably treated on the surface of aluminum, copper alloy, or stainless steel, and more preferably aluminum, copper alloy, and stainless steel.

The shape of the current collector is usually a film shape, but a mesh, a perforated body, a slat body, a porous body, a foam, a molded body of a fiber group, or the like can also be used.

The thickness of the current collector is not particularly limited, but is preferably 1 to 500 μm. The surface of the current collector is preferably roughened by surface treatment.

In the present invention, functional layers, members, or the like may be appropriately interposed or arranged between or outside the layers of the negative electrode current collector, the negative electrode active material layer, the solid electrolyte layer, the positive electrode active material layer, and the positive electrode current collector. The layers may be formed as a single layer or may be formed as a plurality of layers.

< Shell >

The basic structure of the all-solid-state secondary battery can be manufactured by disposing the above layers. The present invention is not limited to the above-described examples, and may be used as it is in the form of a solid-state secondary battery. The case may be metallic or made of resin (plastic). In the case of using a metallic case, for example, an aluminum alloy case and a stainless steel case can be cited. The metallic case is preferably divided into a positive electrode-side case and a negative electrode-side case, and is electrically connected to the positive electrode current collector and the negative electrode current collector, respectively. The positive electrode side case and the negative electrode side case are preferably joined and integrated with each other through a short-circuit prevention gasket.

[ production of sheet containing solid electrolyte ]

The solid electrolyte-containing sheet of the present invention is obtained by applying the solid electrolyte composition of the present invention to a substrate (other layers may be interposed therebetween) or a metal foil as required, and drying or heating (film formation) (heating step). The heating (heating conditions) of the solid electrolyte composition of the present invention means heating the solid electrolyte composition to a temperature (conditions) at which the compound (C) and the compound (D) undergo polymerization. For example, the method includes heating the solid electrolyte composition coated at a temperature at which the compound (C) and the compound (D) do not undergo polymerization reaction to a temperature higher than a temperature at which the polymerization reaction does not proceed, for example, to a temperature higher than a temperature at which the polymerization reaction proceeds. By heating (coating) the solid electrolyte composition in this manner, the compound (C) and the compound (D) can be polymerized in the presence of the polymer (a) and the electrolyte salt (B). Thus, a solid electrolyte layer or an active material layer formed in a sheet (layer) shape can be formed.

The presence of the polymer (a) and the electrolyte salt (B) means that the polymer (a) and the electrolyte salt (B) exist as separate compounds, and include the form in which the polymer (a) dissolves (disperses) the electrolyte salt (B) as an ion conductor.

The conditions under which the compound (C) and the compound (D) are polymerized cannot be determined roughly depending on the type of the polymerization-reactive group and the reaction of the compound (C) and the compound (D), respectively, and the polymerization reaction may be carried out at room temperature (25 ℃). In the case of an example of the reaction conditions, the reaction temperature is, for example, 60℃or higher, preferably 70 to 150℃and more preferably 80 to 120 ℃. The reaction time and the reaction environment can be appropriately set. In addition, various catalysts generally used in the reaction of the above-mentioned polymerization-reactive groups can be used, and light irradiation can be performed as needed.

As the step of applying the solid electrolyte composition, the method described in the following production of the all-solid secondary battery can be used.

In the case of a solid electrolyte sheet for an all-solid-state secondary battery, a substrate for forming a film of the solid electrolyte composition can be peeled off as needed, and a sheet composed of a solid electrolyte layer can be produced.

[ production of all-solid Secondary Battery ]

< all-solid-state secondary battery manufacturing method of (1)

The production of the all-solid-state secondary battery can be carried out by a usual method in addition to the method for producing the solid electrolyte-containing sheet according to the present invention. Specifically, the all-solid secondary battery can be manufactured by forming a layer composed of a solid electrolyte-containing sheet using the solid electrolyte composition or the like of the present invention. Hereinafter, details will be described.

The all-solid-state secondary battery of the present invention can be produced by a method comprising a step of forming a coating film by (via) applying the solid electrolyte composition of the present invention to a metal foil as a current collector.

In the method for producing an all-solid-state secondary battery of the present invention, as described above, in the step of heating the solid electrolyte composition of the present invention, the compound (C) and the compound (D) undergo polymerization reaction, but this is omitted in the following description. In the following description, the composition is coated and heated, but in the present invention, at least the composition may be heated.

For example, a solid electrolyte composition containing a positive electrode active material as a positive electrode material (positive electrode composition) is applied and heated to form a positive electrode active material layer on a metal foil as a positive electrode current collector, thereby producing a positive electrode sheet for an all-solid-state secondary battery. Next, a solid electrolyte composition for forming a solid electrolyte layer is applied and heated on the positive electrode active material layer to form a solid electrolyte layer. Then, a solid electrolyte composition containing a negative electrode active material as a negative electrode material (negative electrode composition) is applied and heated on the solid electrolyte layer to form a negative electrode active material layer. By overlapping the anode current collector (metal foil) on the anode active material layer, an all-solid-state secondary battery having a structure in which the solid electrolyte layer is sandwiched between the cathode active material layer and the anode active material layer can be obtained. The desired all-solid-state secondary battery can be produced by sealing the battery in a case as needed.

In this production method, the solid electrolyte composition of the present invention is used in at least 1 solid electrolyte composition among the positive electrode material, the solid electrolyte composition for forming the solid electrolyte layer, and the negative electrode material, and the above-mentioned generally used solid electrolyte composition or the like is used in the remaining solid electrolyte composition. The same applies to the method described later.

In contrast to the method of forming each layer, an all-solid-state secondary battery can also be manufactured by forming a negative electrode active material layer, a solid electrolyte layer, and a positive electrode active material layer on a negative electrode current collector and overlapping the positive electrode current collector.

As other methods, the following methods can be mentioned. That is, the positive electrode sheet for all-solid secondary batteries was produced as described above. Then, a solid electrolyte composition containing a negative electrode active material as a negative electrode material is coated and heated on a metal foil as a negative electrode current collector to form a negative electrode active material layer, and a negative electrode sheet for an all-solid-state secondary battery is produced. Next, a solid electrolyte layer was formed on the active material layer of any one of these sheets as described above. The other of the positive electrode sheet for all-solid-state secondary batteries and the negative electrode sheet for all-solid-state secondary batteries is laminated on the solid electrolyte layer so that the solid electrolyte layer is in contact with the active material layer. Thus, an all-solid secondary battery can be manufactured.

Further, as other methods, the following methods are exemplified. That is, the positive electrode sheet for all-solid secondary batteries and the negative electrode sheet for all-solid secondary batteries were produced as described above. In addition, a solid electrolyte sheet for an all-solid secondary battery including a solid electrolyte layer is produced by coating and heating a solid electrolyte composition on a substrate. The solid electrolyte layer peeled from the base material is laminated and bonded so as to be sandwiched between the positive electrode sheet for all-solid-state secondary batteries and the negative electrode sheet for all-solid-state secondary batteries. Thus, an all-solid secondary battery can be manufactured.

< formation of layers (film formation) >)

The method of applying the solid electrolyte composition is not particularly limited, and may be appropriately selected. For example, coating (preferably wet coating), spray coating, spin coating, dip coating, slot coating, stripe coating, and bar coating can be cited.

In this case, the solid electrolyte composition may be dried or heat-treated after being applied separately, or may be dried or heat-treated after being applied in multiple layers. The drying or heating temperature of the solid electrolyte composition of the present invention is set to the conditions under which the above-mentioned compound (C) and compound (D) undergo polymerization. The drying or heating temperature of the solid electrolyte composition that is generally used is not particularly limited. The lower limit is preferably 30℃or higher, more preferably 60℃or higher, and still more preferably 80℃or higher. The upper limit is preferably 300℃or lower, more preferably 250℃or lower, and still more preferably 200℃or lower. Drying or heating in such a temperature range can remove the solvent (G) to prepare a solid state. Further, it is preferable from the standpoint that the temperature is not excessively high and the damage to the respective components of the all-solid-state secondary battery can be prevented.

After the coated solid electrolyte composition or the all-solid secondary battery is produced, the layers or the all-solid secondary battery are preferably pressurized. Further, it is also preferable to apply pressure in a state where the layers are laminated. As the pressurizing method, a hydraulic cylinder press machine or the like can be cited. The pressurizing pressure is not particularly limited, and is generally preferably in the range of 50 to 1500 MPa.

Also, the coated solid electrolyte composition may be heated while being pressurized. The heating temperature is not particularly limited, and is generally in the range of 30 to 300 ℃. The pressing can be performed at a temperature higher than the glass transition temperature of the inorganic solid electrolyte.

The pressurization may be performed in a state where the solvent (G) is dried in advance, or may be performed in a state where the solvent (G) remains.

The compositions may be applied simultaneously, or may be applied, dried, and punched simultaneously and/or stepwise. Lamination may be performed by transfer after application to the respective substrates.

The environment under pressure is not particularly limited, and may be any of the atmosphere, under dry air (dew point-20 ℃ C. Or lower), in an inert gas (for example, in argon, helium, or nitrogen), and the like.

The pressing time may be a short time (for example, within several hours) in which a high pressure is applied, or a long time (1 day or more) in which a moderate pressure is applied. In addition to the sheet for an all-solid-state secondary battery, for example, in the case of an all-solid-state secondary battery, a restraining tool (screw tightening pressure or the like) of the all-solid-state secondary battery can be used to continue applying a moderate level of pressure.

The pressing pressure may be uniform or different with respect to the pressed portion such as the surface of the sheet.

The pressing pressure can be changed according to the area of the pressed portion and the film thickness. In addition, the same portion may be changed in stages at different pressures.

The stamping surface may be smooth or rough.

< initialization >

The all-solid secondary battery manufactured as described above is preferably initialized after manufacture or before use. The initialization is not particularly limited, and for example, the initial charge and discharge may be performed in a state where the pressing pressure is increased, and then the pressure is released until the pressure reaches the normal use pressure of the all-solid-state secondary battery.

[ use of all-solid Secondary Battery ]

The all-solid-state secondary battery of the present invention can be applied to various uses. The application mode is not particularly limited, and examples thereof include a notebook computer, a pen-input computer, a mobile computer, an electronic book reader, a mobile phone, a wireless telephone subset, a pager, a hand-held terminal, a portable facsimile machine, a portable copying machine, a portable printer, a stereo headset, a camcorder, a liquid crystal television, a portable vacuum cleaner, a portable CD, a compact disc, an electric shaver, a transceiver, an electronic organizer, a calculator, a portable recorder, a radio, a standby power supply, a memory card, and the like when mounted on an electronic device. Examples of other consumer products include automobiles (electric automobiles, etc.), electric vehicles, motors, lighting devices, toys, game machines, load regulators, watches, flash lamps, cameras, medical devices (cardiac pacemakers, hearing aids, shoulder massage machines, etc.), and the like. Moreover, it can be used as various military supplies and aviation supplies. And, can also be combined with solar cells.

In the present invention, an all-solid-state secondary battery refers to a secondary battery in which a positive electrode, a negative electrode, and an electrolyte are all made of solids. In other words, it is distinguished from, for example, an electrolyte type secondary battery using a carbonate-based solvent as an electrolyte. The invention is premised on a polymer all-solid-state secondary battery. The all-solid-state secondary battery is divided into: as the electrolyte, a (organic) polymer all-solid-state secondary battery using a polymer solid electrolyte (polymer electrolyte) in which an electrolyte salt such as LiTFSI is dissolved in a polymer compound such as polyethylene oxide; and an inorganic all-solid-state secondary battery using the above-mentioned Li-P-S glass, LLT, LLZ or other inorganic solid electrolyte. The inorganic compound may be applied to the polymer all-solid secondary battery, and the inorganic compound may be applied as a positive electrode active material, a negative electrode active material, an inorganic solid electrolyte, and an additive.

The polymer solid electrolyte is an inorganic solid electrolyte that contains a polymer compound in which an electrolyte salt is dissolved as an ion conductor, unlike the inorganic compound described above as an ion conductor. The inorganic solid electrolyte itself does not deintercalate cations (Li ions), but exhibits an ion transport function. In contrast, a material that is added to an electrolyte solution or a solid electrolyte layer to desorb cations (Li ions) and serves as a source of ions may be referred to as an electrolyte. When distinguished from the electrolyte as the ion transport material described above, it is referred to as "electrolyte salt" or "supporting electrolyte". Examples of the electrolyte salt include LiTFSI.

Examples

The present invention will be described in further detail with reference to examples, but the present invention is not limited thereto. In the following examples, "parts" and "%" indicating compositions are mass-based unless otherwise specified.

Example 1

Preparation example 1: solid electrolyte composition, sheet containing solid electrolyte, and method for producing all-solid secondary battery

(preparation of solid electrolyte composition S-1)

To a 50mL sample bottle were added 2.5g of polyethylene oxide (PEO, mw:10 ten thousand manufactured by Aldrich Co.), 1.0g of lithium bis (trifluoromethylsulfonyl) imide (LiTFSI, wako Pure Chemical Industries manufactured by Ltd.), 0.133g of tris (2-aminoethyl) amine (TAEA, wako Pure Chemical Industries manufactured by Ltd.), 0.277g of butanediol diglycidyl ether (BDGE, wako Pure Chemical Industries manufactured by Ltd.), and 25g of acetonitrile (Wako Pure Chemical Industries manufactured by Ltd.) which were dissolved at 25℃to obtain a solid electrolyte composition S-1.

(production of solid electrolyte-containing sheet SS-1)

The obtained solid electrolyte composition S-1 was coated on a Polytetrafluoroethylene (PTFE) sheet using an applicator (trade name: SA-201, baking applicator, manufactured by ster SANGYO CO,. Ltd.). The coated solid electrolyte composition S-1 was dried under nitrogen atmosphere at 100 ℃ for 30 minutes, and further air-dried at 80 ℃ for 2 hours. In this way the amino group of TAEA is reacted with the epoxy group of BDGE in the presence of PEO and LiTFSI. Thus, a solid electrolyte layer having a base portion composed of a crosslinked polymer having a 1, 2-aminoalcohol structure as a crosslinked structure and an ion conductor composed of PEO and LiTFSI was formed. Thus, a solid electrolyte-containing sheet SS-1 having a solid electrolyte layer with a layer thickness of 150 μm was obtained.

(production of all-solid Secondary Battery SB-1)

Production of positive electrode sheet for all-solid secondary battery

To a 50mL sample bottle, 0.82g of acetylene Black (Denka Black (trade name), manufactured by Denka Company Limited) and 5.51g of N-methylpyrrolidone (NMP, wako Pure Chemical Industries, ltd.) were added, and the mixture was mixed at 2000rpm for 5 minutes at room temperature (25 ℃) using a rotation and revolution mixer (ARE-310 (trade name, manufactured by THINKY). Next, 10.94g LiFePO was added ₄ (LFP, manufactured by Hohsen Corp.) 2.01g of NMP, and was stirred at room temperature using a rotation/revolution stirrer(25 ℃) was mixed for 2 minutes at 2000 rpm. Then, 0.23g of PVdF (KYNAR 301F (trade name), manufactured by ARKEMA Co., ltd.) and 7.75g of NMP were added, and the mixture was mixed at 2000rpm for 2 minutes at room temperature (25 ℃ C.) using a rotation and revolution mixer. Using the applicator described above: SA-201 (trade name) the obtained slurry was coated on an aluminum foil having a thickness of 20. Mu.m, and air-dried at 100℃for 2 hours. The obtained sheet was punched out at 5kN/cm using a roll press machine, whereby a positive electrode sheet for an all-solid-state secondary battery having a positive electrode active material layer thickness of 30 μm was produced.

Fabrication of all-solid-state secondary battery SB-1

Hereinafter, the production of the all-solid-state secondary battery SB-1 will be described with reference to fig. 2.

A circular plate-shaped Li foil (thickness 100 μm, honjo Metal co., ltd.) cut to a diameter of 15mm was put into a stainless steel 2032 type button cell case 16 in which a separator and a gasket (both not shown in fig. 2) were assembled. Next, the PTFE sheet was cut into a disk shape having a diameter of 16mm, and a solid electrolyte-containing sheet (solid electrolyte layer) SS-1, from which the PTFE sheet was peeled, was superimposed on the Li foil so that the Li foil was in contact with the solid electrolyte layer. Further, a disk-shaped positive electrode sheet for all-solid-state secondary batteries having a diameter of 13mm was cut on the solid electrolyte layer in an overlapping manner so that the solid electrolyte layer was in contact with the positive electrode active material layer, and an all-solid-state secondary battery 18 was produced. The solid electrolyte sheet 17 for all-solid secondary batteries in the 2032 type button cell case has a laminated structure of Li foil/solid electrolyte layer/positive electrode active material layer/aluminum foil.

Preparation examples 2 to 10: solid electrolyte composition, sheet containing solid electrolyte, and method for producing all-solid secondary battery

(preparation of solid electrolyte composition)

As shown in Table 3-1 below, solid electrolyte compositions S-2 to S-10 were each prepared in the same manner as solid electrolyte composition S-1, except that the respective components and the amounts used were changed.

Solid electrolyte-containing sheets SS-2 to SS-10 and all-solid secondary batteries SB-2 to SB-10 were produced in the same manner as the electrolyte sheet SS-1 for all-solid secondary batteries and the all-solid secondary battery SB-1, respectively, except that the obtained solid electrolyte compositions S-2 to S-10 were used in place of the solid electrolyte composition S-1, respectively.

In the preparation of each of the above-described solid electrolyte compositions, the components not shown in Table 3-1, including the amounts used, are unchanged as long as they are not specifically described.

Among the solid electrolyte-containing sheets, the solid electrolyte-containing sheets SS-2 to SS-6, SS-9 and SS-10 are composed of crosslinked polymers having a 1, 2-aminoalcohol structure as a crosslinked structure, the solid electrolyte-containing sheet SS-7 is composed of crosslinked polymers having a urethane bond as a crosslinked structure, and the solid electrolyte-containing sheet SS-8 is composed of crosslinked polymers having an ester bond as a crosslinked structure.

Solid electrolyte composition for comparative example, sheet containing solid electrolyte, and production of all-solid secondary battery

(1) Preparation of solid electrolyte composition T-1 and T-2, etc

According to examples 1-2 described in patent document 1, a solid electrolyte composition T-1 was prepared. A solid electrolyte-containing sheet TS-1 and an all-solid secondary battery TB-1 were produced in the same manner as the electrolyte sheet SS-1 for an all-solid secondary battery and the all-solid secondary battery SB-1, except that the obtained solid electrolyte composition T-1 was used in place of the solid electrolyte composition S-1.

Then, according to example 1 described in patent document 2 (Si-LE-2 shown below is set to the same ratio as example 1-2 of patent document 1, that is, "the number of moles of oxygen atoms in the ether unit" to be the basis of the amount of the electrolyte salt (C) used is added to the number of moles of oxygen atoms in the ether unit included in each liquid siloxane derivative), a solid electrolyte composition T-2 was prepared in the mass ratio shown in table 3-1. In the same manner as in the electrolyte sheet for all-solid-state secondary battery SS-1 and all-solid-state secondary battery SB-1 except that the obtained solid electrolyte composition T-2 was used instead of the solid electrolyte composition S-1, a sheet TS-2 containing a solid electrolyte and an all-solid-state secondary battery TB-2 were produced.

In the preparation of each of the solid electrolyte compositions T-1 and T-2, the components not shown in Table 3-1, including the amounts used, were not changed unless otherwise specified.

In addition, although components that do not correspond to the polymer (A) and the compound (C) are also present in the components used in the solid electrolyte compositions T-1 and T-2, these components are shown in the same column of Table 3-1 for convenience.

(2) Preparation of solid electrolyte composition T-3 and the like

As shown in Table 3-1 below, a solid electrolyte composition T-3 was prepared in the same manner as in solid electrolyte composition S-1, except that the respective components and the amounts used were changed.

A solid electrolyte-containing sheet TS-3 and an all-solid secondary battery TB-3 were produced in the same manner as the electrolyte sheet SS-1 for an all-solid secondary battery and the all-solid secondary battery SB-1, respectively, except that the obtained solid electrolyte composition T-3 was used in place of the solid electrolyte composition S-1.

In the preparation of the above-described solid electrolyte composition, as far as not specifically described, the components not shown in table 3-1, including the amounts used, are not changed.

In the solid electrolyte-containing sheet TS-3, the matrix portion contained together with the ion conductor is composed of a linear polymer having an ester bond.

(3) Preparation of solid electrolyte composition T-4 and the like

As a comparative solid electrolyte composition T-4, TAEA and BDGE were polymerized in advance in the same amount as that of the solid electrolyte composition S-1, and reactants of TAEA and BDGE were synthesized. The reactant, PEO and LiTFSI were mixed in the same amount as the solid electrolyte composition S-1. However, the reactant and PEO and LiTFSI cannot be uniformly mixed, and the solid electrolyte composition T-4 cannot be prepared.

Solid electrolyte composition and measurement of sheet containing solid electrolyte

(calculation of the mass ratio of the content of each component)

The mass ratio of the contents of the polymer (A), the electrolyte salt (B), the compound (C) and the compound (D) in the solid electrolyte compositions S-1 to S-10 and T-1 to T-3 is calculated from the amounts of the components used in the preparation of the solid electrolyte compositions. The results are shown in Table 3-1.

(ratio of polymerization-reactive groups R) ^G Is calculated by (a) and (b)

According to the content (mole) of the compounds (C) and (D) used in the preparation of each solid electrolyte composition, and according to the above formula (R ^G ) Calculating the ratio R of the polymerization-reactive groups in each of the solid electrolyte compositions S-1 to S-10 and T-3 ^G . The results are shown in Table 3-1.

(measurement of solid content concentration)

The solid content concentrations in the respective solid electrolyte compositions S-1 to S-10 and T-1 to T-3 were calculated from the use amounts of the respective components used in the preparation of the respective solid electrolyte compositions. The results are shown in Table 3-1.

(measurement of volatile content)

The volatile content in each of the solid electrolyte-containing sheets SS-1 to SS-10 and TS-1 to TS-3 was measured in the following manner. That is, the solid electrolyte-containing sheet, of which the mass W1 was measured in advance, was left to stand for 4 hours at 250 ℃ under a vacuum (pressure 10Pa or less) environment. Then, the mass W2 of the solid electrolyte-containing sheet was measured. The content of volatile components in the solid electrolyte-containing sheet was calculated from the masses W1 and W2 before and after the placement according to the following formula. The results are shown in Table 3-2.

The content of volatile components (mass%): (W1-W2)/W1

< Battery Performance test >

(measurement of ion conductivity)

The method of measuring ion conductivity will be described below with reference to fig. 2.

The solid electrolyte-containing sheets SS-1 to SS-10, TS-1 to TS-3 obtained in the above were cut into a disk shape having a diameter of 14.5mm, and the PTFE sheet was peeled off to be put into the button cell case 16 as the solid electrolyte sheet 17 for an all-solid secondary battery shown in fig. 2. Specifically, a disk-shaped aluminum foil (not shown in fig. 2) cut to a diameter of 15mm was brought into contact with the solid electrolyte layer of the solid electrolyte-containing sheet, and a separator and a gasket (not shown in fig. 2) were assembled and placed in a stainless steel 2032 type button cell case 16. An all-solid-state secondary battery 18 for measuring ion conductivity was fabricated by pressing the button cell case 16.

The ion conductivity was measured using the obtained all-solid-state secondary battery 18 for ion conductivity measurement. Specifically, ac impedance measurement was performed in a constant temperature bath at 60 ℃ using 1255B FREQUENCY RESPONSE ANALYZER (frequency response analyzer) (trade name) manufactured by SOLARTRON corporation until the voltage amplitude was 5mV and the frequency was 1MHz to 1Hz. Thus, the resistance of the sample in the film thickness direction was obtained, and calculated by the following equation.

Ionic conductivity (mS/cm) =

1000X sample film thickness (cm)/(resistance (. OMEGA.). Times.sample area (cm) ² ) … … (A)

In the formula (a), the sample film thickness and the sample area are measured before the solid electrolyte-containing sheet is placed in the 2032 type button cell case 16.

Determines which of the following evaluation levels the obtained ion conductivity is included in, and the results thereof are shown in Table 3-2. The ionic conductivity in this test was rated as "6" or more.

Rating (r-

8：2×10 ^-4 S/cm or more

7：1×10 ^-4 S/cm or more and less than 2X 10 ^-4 S/cm

6：7×10 ^-5 S/cm or more and less than 1×10 ^-4 S/cm

5：4×10 ^-5 S/cm or more and less than 7×10 ^-5 S/cm

4：1×10 ^-5 S/cm or more and less than 4×10 ^-5 S/cm

3：5×10 ^-6 S/cm or more and less than 1×10 ^-5 S/cm

2：1×10 ^-6 S/cm or more and less than5×10 ^-6 S/cm

1: less than 1X 10 ^-6 S/cm

(evaluation of durability)

The obtained all-solid-state secondary batteries SB-1 to SB-10 and TB-1 to TB-3 were evaluated by a potentiostat (1470 (trade name), manufactured by Solartron Corp.) at 60 ℃. Evaluation was performed from the start of discharge at 0.2mA/cm ² Is discharged until the cell voltage reaches 1.0V. At 0.2mA/cm ² Charging is performed until the battery voltage reaches 2.5V. The discharge and charge were taken as 1 cycle. The discharge and charge were repeated, and durability was evaluated by the number of cycles initially representing the voltage abnormality behavior.

The abnormal voltage behavior in this test is a case where a curve is generated in the charge curve at the time of charging and a voltage drop is confirmed, or a case where the charge and discharge efficiency is 97% or less.

The number of cycles in which the abnormal voltage behavior was confirmed was determined to be included in the following evaluation level, and the results are shown in table 3-2. The durability in this test was rated as "5" or more.

Rating (r-

8:500 cycles above

7:300 cycles above and less than 500 cycles

6:200 cycles above and less than 300 cycles

5:100 cycles above and less than 200 cycles

4:70 cycles above and less than 100 cycles

3:40 cycles above and less than 70 cycles

2:20 cycles above and less than 40 cycles

1: less than 20 cycles

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< annotation of Table >)

(A) The method comprises the following steps Polymer (A)

(B) The method comprises the following steps Electrolyte salt (B)

(C) The method comprises the following steps Compound (C)

(D) The method comprises the following steps Compound (D)

In columns (C) and (D) of Table 3-1, numerals in parentheses below the abbreviations of the compounds represent the numbers of the polymerization-reactive groups in 1 molecule.

Abbreviations for the Compounds

PEO (10): polyethylene oxide (Mw: 10 ten thousand)

PEO (60): polyethylene oxide (Mw: 60 ten thousand)

PEG (06): polyethylene glycol (Mw: 6 thousands)

PEO (100): polyethylene oxide (Mw: 100 ten thousand)

PA (14.5): polymers synthesized under the following conditions

A mixed solution was prepared by mixing 22.4g of poly (ethylene glycol) methyl ether acrylate (number average molecular weight: 5000, manufactured by Aldrich Co., ltd.), 0.2g of a polymerization initiator V-601 (trade name, wako Pure Chemical Industries, manufactured by Ltd.) and 30.0g of tetrahydrofuran. Then, a reflux cooling tube and a gas introducing plug were attached, nitrogen gas was introduced at a flow rate of 200mL/min for 10 minutes, and then the prepared mixed solution was added dropwise to a 200mL three-necked flask heated to 80℃over 2 hours, followed by stirring at 80℃for a further 2 hours. The obtained solution was added to 500g of ethanol, and the obtained solid was dried under vacuum at 60 ℃ for 5 hours, thereby obtaining PA. The mass average molecular weight of the obtained PA was 145,000.

TAEA: tris (2-aminoethyl) amine

BDGE:1, 4-butanediol diglycidyl ether

TMPTGE: trimethylol propane triglycidyl ether

TMP: trimethylolpropane

MDI:4,4' -diisocyanato methyl diphenyl ester

SBC: sulfonyl chloride

And (2) HMG: hexamethylene glycol

Si-LE-1: liquid siloxane derivatives (Mw: 779) shown below

Si-LE-2: liquid siloxane derivatives (Mw: 3764) shown below

LiTFSI: lithium bis (trifluoromethanesulfonyl) imide: liN (CF) ₃ SO ₂ ) ₂

LiFSI: lithium bis (fluorosulfonyl) imide: liN (FSO) ₂ ) ₂

TMPTA: trimethylolpropane triacrylate

PEGMA: methoxy polyethylene glycol monomethacrylate (Mw: 496)

PEGDMA: polyethylene glycol dimethacrylate (Mw: 536)

[ chemical formula 8]

The results shown in tables 3-1 and 3-2 are shown below.

Neither the solid electrolyte composition T-1 containing no compound (D) nor the solid electrolyte composition T-2 containing no polymer (a) can impart high ionic conductivity and excellent durability to the all-solid-state secondary battery. Further, it was found that even though the solid electrolyte composition T-3 contains the polymer (a) and the electrolyte salt (B), it does not contain the compound (C) and contains only the compound having only 2 polymerization-reactive groups, the durability of the all-solid secondary battery could not be improved. Further, if the compound (C) and the compound (D) are reacted to form a reactant, the solid electrolyte composition T-4 cannot be prepared.

In contrast, the solid electrolyte compositions S-1 to S-10 of the present invention containing the polymer (A), the electrolyte salt (B), the compound (C) and the compound (D) can impart ion conductivity and durability to all solid-state secondary batteries at high levels. It is assumed that the reason for this is that in the solid electrolyte compositions S-1 to S-10, when a sheet containing a solid electrolyte is produced, the compound (C) and the compound (D) undergo polymerization reaction in the presence of the polymer (a) and the electrolyte salt (B) to form a sheet in a state in which the ionic conductor and the matrix site interact with each other.

In particular, the solid electrolyte compositions S-1 to S-9 contain PEO, which is generally considered to have low mechanical strength, as the polymer (A). However, each of the solid electrolyte compositions contains an electrolyte salt (B), a compound (C) and a compound (D) in addition to the polymer (a), and can exhibit high durability while maintaining high ionic conductivity of the all-solid-state secondary battery. All of the solid-state secondary batteries SB-1 to SB-10 of the present invention are provided with a Li foil as a negative electrode, which is considered to be prone to lithium dendrite generation and to reduce the durability of the battery. However, it is found that since the solid electrolyte layers of these all-solid secondary batteries are formed from the solid electrolyte compositions S-1 to S-10 of the present invention, they exhibit high durability even when a Li foil is provided as a negative electrode.

Example 2 >

In example 2, a solid electrolyte composition containing a sulfide-based inorganic solid electrolyte as the inorganic solid electrolyte (E), a solid electrolyte-containing sheet and an all-solid-state secondary battery using the solid electrolyte composition were prepared or produced, and the battery performance of the all-solid-state secondary battery was evaluated.

(Synthesis of sulfide-based inorganic solid electrolyte)

2.42g of lithium sulfide (Li) was weighed out separately in a glove box under argon atmosphere (dew point-70 ℃ C.) ₂ S, aldrich company, purity > 99.98%) and 3.90g of phosphorus pentasulfide (P) ₂ S ₅ Manufactured by Aldrich company, purity > 99%) and was put into an agate mortar, and mixed for 5 minutes using an agate cream stick. Li (Li) ₂ S and P ₂ S ₅ Is Li in terms of molar ratio ₂ S:P ₂ S ₅ ＝75:25。

66g of zirconia beads having a diameter of 5mm were put into a 45mL zirconia vessel (manufactured by Fritsch co., ltd.) and the total amount of the above-mentioned mixture of lithium sulfide and phosphorus pentasulfide was put into the vessel, and the vessel was completely sealed under an argon atmosphere. The vessel was mounted in a planetary ball mill P-7 (trade name, fritsch co., ltd.) and subjected to mechanical grinding at a rotation speed of 510rpm for 20 hours at a temperature of 25 ℃ to obtain 6.20g of a sulfide-based inorganic solid electrolyte (LPS) of yellow powder.

To 100 parts by mass of solid electrolyte composition S-3, 70 parts by mass of synthesized LPS was added to prepare solid electrolyte composition S-3 (LPS).

A solid electrolyte-containing sheet SS-3 (LPS) and an all-solid secondary battery SB-3 (LPS) were produced in the same manner as the electrolyte sheet SS-3 for an all-solid secondary battery and the all-solid secondary battery SB-3, respectively, except that the obtained solid electrolyte composition S-3 (LPS) was used in place of the solid electrolyte composition S-3.

The electrolyte sheet SS-3 (LPS) for all-solid-state secondary batteries and the all-solid-state secondary battery SB-3 (LPS) thus produced were evaluated in the same manner as the measurement of the ion conductivity and the evaluation of the durability. As a result, excellent results similar to those of the electrolyte sheet SS-3 for all-solid-state secondary batteries and the all-solid-state secondary battery SB-3 were obtained regarding ion conductivity and durability.

Example 3 >

In example 3, a solid electrolyte composition containing an oxide-based inorganic solid electrolyte as the inorganic solid electrolyte (E), a solid electrolyte-containing sheet and an all-solid-state secondary battery using the solid electrolyte composition were prepared or produced, and the battery performance of the all-solid-state secondary battery was evaluated.

Except for La _0.55 Li _0.35 TiO ₃ (LLT, TOYOSHIMA MANUFACTURING co., ltd. Manufactured) instead of LPS, a solid electrolyte composition S-3 (LLT) was prepared in the same manner as the solid electrolyte composition S-3 (LPS).

A solid electrolyte-containing sheet SS-3 (LLT) and an all-solid secondary battery SB-3 (LLT) were produced in the same manner as the electrolyte sheet SS-3 for an all-solid secondary battery and the all-solid secondary battery SB-3, respectively, except that the obtained solid electrolyte composition S-3 (LLT) was used in place of the solid electrolyte composition S-3.

The electrolyte sheet SS-3 (LLT) for all-solid secondary batteries and the all-solid secondary battery SB-3 (LLT) thus produced were evaluated in the same manner as the measurement of the ionic conductivity and the evaluation of the durability. As a result, excellent results similar to those of the electrolyte sheet SS-3 for all-solid-state secondary batteries and the all-solid-state secondary battery SB-3 were obtained regarding ion conductivity and durability.

Example 4 >

In example 4, a solid electrolyte composition containing the active material (F), a solid electrolyte-containing sheet and an all-solid-state secondary battery using the solid electrolyte composition were prepared or produced, and the battery performance of the all-solid-state secondary battery was evaluated.

(preparation of composition for Positive electrode)

To a 50mL sample bottle, 0.82g of acetylene Black (Denka Black (trade name), manufactured by Denka Company Limited), 5.51g of NMP (Wako Pure Chemical Industries, manufactured by Ltd.) and 1.0g of PEO (Mw: 10 ten thousand, manufactured by Aldrich), 0.4g of LiTFSI (lithium bis (trifluoromethylsulfonyl) imide (Wako Pure Chemical Industries, manufactured by Ltd.), 0.05g of tris (2-aminoethyl) amine (TAEA, wako Pure Chemical Industries, manufactured by Ltd.), 0.11g of butanediol diglycidyl ether (BDGE, wako Pure Chemical Industries, manufactured by Ltd.) were added, and the mixture was mixed at 2000rpm for 5 minutes at room temperature (25 ℃) using a rotation revolution stirrer (ARE-310 (trade name), manufactured by THINKY Co.). Next, 10.94g of LFP (manufactured by Hohsen Corp.) and 2.01g of NMP were added, and mixed at 2000rpm for 2 minutes at room temperature (25 ℃) using a rotation and revolution mixer. Then, 0.23g of PVdF (KYNAR 301F (trade name), manufactured by ARKEMA Co., ltd.) and 7.75g of NMP were added, and the mixture was mixed at 2000rpm for 2 minutes at room temperature (25 ℃) using a rotation and revolution mixer to obtain a composition for positive electrode (solid electrolyte composition) SS-1 (LFP).

Through an applicator? trade name: SA-201 baking type applicator, manufactured by TESTER SANGYO CO,. LTD. The obtained composition for positive electrode SS-1 (LFP) was coated on aluminum foil having a thickness of 20 μm, and air-dried at 100℃for 2 hours. Thus, the amino groups of TAEA and the epoxy groups of BDGE were reacted in the presence of PEO and LiTFSI. Thus, an ion conductor composed of PEO and LiTFSI and a solid electrolyte layer containing a matrix site having a 1, 2-amino alcohol structure were formed. The resultant sheet was pressed at 5kN/cm by a roll press machine to obtain a positive electrode sheet SS-1 (LFP) for an all-solid secondary battery. The thickness of the positive electrode active material layer was 30. Mu.m.

In the production of the all-solid-state secondary battery SB-1, the durability was evaluated for the all-solid-state secondary battery (a) produced in the same manner as the all-solid-state secondary battery SB-1 except that the obtained positive electrode sheet SS-1 (LFP) for all-solid-state secondary battery was used instead of the positive electrode sheet for all-solid-state secondary battery. The all-solid secondary battery (a) exhibits excellent durability. It was also confirmed that the battery voltage after 10 seconds of discharge at the 3 rd discharge in the durability test was higher, lower than the resistance of the all-solid-state secondary battery SB-1, and also excellent in resistance.

The present invention has been described in connection with the embodiments thereof, and it is to be understood that the invention is not limited to the details of the description unless otherwise specified, and is to be construed broadly without departing from the spirit and scope of the invention as set forth in the appended claims.

The present application claims priority based on japanese patent application 2017-141738 of the japanese application, 7-21, which is incorporated herein by reference and the contents of which are incorporated as part of the description of the present specification.

Symbol description

1-negative electrode current collector, 2-negative electrode active material layer, 3-solid electrolyte layer, 4-positive electrode active material layer, 5-positive electrode current collector, 6-working site, 10-all-solid-state secondary battery, 16-2032 button cell case, solid electrolyte sheet for 17-all-solid-state secondary battery or all-solid-state secondary battery sheet, 18-all-solid-state secondary battery.

Claims

1. A solid electrolyte composition comprising: a polymer (A) having a mass average molecular weight of 5000 or more; an electrolyte salt (B) having ions of a metal belonging to group 1 or group 2 of the periodic table; a compound (C) having 3 or more polymerization-reactive groups; and a compound (D) having 2 or more polymerization-reactive groups which are different from the polymerization-reactive groups of the compound (C) and which are capable of undergoing polymerization reaction with the polymerization-reactive groups of the compound (C),

The polymer (A) does not have a structure capable of reacting with the compound in a molecule other than the terminal of the molecular chain C) and the group which is polymerized by the polymerization-reactive group of the compound (D),

the solid electrolyte composition is a solid electrolyte composition for forming a solid electrolyte layer comprising an ion conductor and a matrix site composed of a crosslinked polymer,

the polymer (a) and the electrolyte salt (B) form the ion conductor, and the compound (C) and the compound (D) form the crosslinked polymer.

2. The solid electrolyte composition according to claim 1, wherein,

the compound (C) and the compound (D) may react to form a crosslinked polymer that does not exhibit ionic conductivity of a metal of group 1 or group 2 of the periodic table.

3. The solid electrolyte composition according to claim 1 or 2, wherein,

the polymerization-reactive group of the compound (C) and the polymerization-reactive group of the compound (D) are each 1 polymerization-reactive group selected from the following polymerization-reactive group (a),

< group (a) >, a polymerization-reactive group

Hydroxy, amino, carboxyl, alkoxycarbonyl, haloformyl, sulfo, carbamoyl, formyl, isocyanate, oxetanyl, epoxy, dicarboxylic anhydride, silyl, alkynyl, alkenyl, bromo, chloro, iodo, diazo, azido, and nitrile oxide groups.

4. The solid electrolyte composition according to claim 1 or 2, wherein,

the following formula (R) ^G ) Ratio R of defined polymerization-reactive groups ^G Greater than 0.8 and less than 1.2,

(R) ^G )：R ^G = [ number of polymerization-reactive groups in molecule of compound (C) 1×content (mol) of compound (C) in solid electrolyte composition]Number of polymerization-reactive groups in molecule of Compound (D) 1X content (mol) of Compound (D) in solid electrolyte composition]。

5. The solid electrolyte composition according to claim 1 or 2, wherein,

the combination of the polymerization-reactive group of the compound (C) and the polymerization-reactive group of the compound (D) is any one of the combinations (C1) to (C9) shown below,

< combination of polymeric reactive groups >

(C1) Amino-carboxyl (C2) amino-isocyanato

(C3) Amino-oxetanyl (C4) amino-epoxy

(C5) Amino-dicarboxylic anhydride (C6) epoxy-carboxyl

(C7) Azido-alkynyl (C8) oxy-nitrile-alkynyl

(C9) Hydroxy-isocyanate groups.

6. The solid electrolyte composition according to claim 1 or 2, wherein,

the combination of the polymerization-reactive group of the compound (C) and the polymerization-reactive group of the compound (D) is any one of the combinations (C3), (C4), (C6) to (C8) shown below,

< combination of polymeric reactive groups >

(C3) Amino-oxetanyl (C4) amino-epoxy

(C6) Epoxy-carboxy (C7) azido-alkynyl

(C8) Nitrile oxide-alkynyl groups.

7. The solid electrolyte composition according to claim 1 or 2, wherein,

the contents of the polymer (A), the electrolyte salt (B), the compound (C) and the compound (D) in the solid electrolyte composition are calculated by mass ratio as the polymer (A), the electrolyte salt (B), the compound (C) and the compound (D) =1:0.05-2.50:0.04-2:0.04-2.

8. The solid electrolyte composition according to claim 1 or 2, wherein,

the compound (D) has 3 or more of the polymerization-reactive groups.

9. The solid electrolyte composition according to claim 1 or 2, which contains an inorganic solid electrolyte (E).

10. The solid electrolyte composition according to claim 1 or 2, which contains an active material (F).

11. The solid electrolyte composition according to claim 1 or 2, which contains a solvent (G).

12. The solid electrolyte composition according to claim 11, wherein,

the solid content concentration is 5 to 40 mass%.

13. A solid electrolyte-containing sheet having a layer composed of the solid electrolyte composition according to any one of claims 1 to 12.

14. The solid electrolyte-containing sheet according to claim 13, which has:

the polymer (A),

The electrolyte salt (B)

A reactant of the compound (C) with the compound (D).

15. An all-solid-state secondary battery, comprising: a positive electrode active material layer, a negative electrode active material layer, and a solid electrolyte layer between the positive electrode active material layer and the negative electrode active material layer, wherein,

at least 1 of the positive electrode active material layer, the negative electrode active material layer, and the solid electrolyte layer is a layer composed of the solid electrolyte composition according to any one of claims 1 to 12.

16. The all-solid secondary battery according to claim 15, wherein,

17. The all-solid secondary battery according to claim 15, wherein,

the negative electrode active material layer is a lithium layer.

18. A method for producing a sheet containing a solid electrolyte, wherein,

the solid electrolyte composition according to any one of claims 1 to 12, wherein the compound (C) and the compound (D) are polymerized in the presence of the polymer (a) and the electrolyte salt (B).

19. A manufacturing method of an all-solid secondary battery, which manufactures an all-solid secondary battery by the manufacturing method of claim 18.